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Global agricultural productivity and food security are threatened by climate change, the growing world population, and the difficulties posed by the pandemic era. To overcome these challenges and meet food requirements, breeders have applied and implemented different advanced techniques that accelerate plant development and increase crop selection effectiveness. However, only two or three generations could be advanced annually using these approaches. Speed breeding (SB) is an innovative and promising technology to develop new varieties in a shorter time, utilizing the manipulation of controlled environmental conditions. This strategy can reduce the generation length from 2.5 to 5 times compared to traditional methods and accelerate generation advancement and crop improvement, accommodating multiple generations of crops per year. Beside long breeding cycles, SB can address other challenges related to traditional breeding, such as response to environmental conditions, disease and pest management, genetic uniformity, and improving resource efficiency. Combining genomic approaches such as marker-assisted selection, genomic selection, and genome editing with SB offers the capacity to further enhance breeding efficiency by reducing breeding cycle time, enabling early phenotypic assessment, efficient resource utilization, and increasing selection accuracy and genetic gain per year. Genomics-assisted SB holds the potential to revolutionize plant breeding by significantly accelerating the identification and selection of desirable genetic traits, expediting the development of improved crop varieties crucial for addressing global agricultural challenges.

We experimentally study single-shot laser ablation of GaSb, GaAs, GaP and GaN, for laser pulse durations ranging from 200 fs to 20 ps. We find that the laser ablation threshold fluence of GaSb is almost independent of pulse duration, whereas the ablation threshold for GaN depends strongly on pulse duration. More generally we find that the larger the bandgap, the stronger the dependence of pulse duration. This is expected, as intrinsic laser absorption is mainly linear when the bandgap is small compared to the photon energy, whereas a larger bandgap requires strong field ionization. Thus a larger bandgap leads to a stronger influence of the peak intensity of the pulse and therefore a stronger dependence on the pulse duration, when compared to smaller bandgaps.

III-V semiconductor material based nanowires have been extensively studied and shown to be a very exciting building block for future electronics. Material systems such as GaSb show a lot of promise in optoelectric and thermoelectric generation applications because of its high electron mobility and small bandgap. Although there is a lot of research about III-V nanowires, a gap in understanding antimony based nanowire growth is present. The surfactant effect of Sb makes growth of antimony based nanoowires challenging. The aim of this master thesis is to investigate direct nucleation of GaSb from both Au and Sn seed particles which would help to develop a method for direct nucleation. The study is carried out in an environmental transmission electron microscope which enables the nucleation of GaSb to be studied and recorded in-situ. Au seeded nucleation occurred at high amounts of Ga present in the particle, above 90 at.%, whilst it is shown that Sn seeded nucleation is possible for a very broad range of seed particle compositions, between 12 at.% and 70 at.%. The Au seeded nanowires were much bigger than the Sn seeded, 100 to 200 nm and 25 to 50 nm respectively, which is related to the Ga amount in the seed particle. This shows that Sn seeded GaSb direct nucleation gives much more promise if the nanowires would be integrated into electrical devices where smaller diameter nanowires are needed. For Au seeded GaSb nanowires twin planes were observed in the zinc blende crystal structure which indicated a possibility of polytypism in GaSb nanowires which has not been reported yet. The observation of polytypism in GaSb is the first step to crystal phase engineering in GaSb nanowires which could be crucial in applications such as nanowire quantum dot devices. This thesis serves as a guideline and a starting point for further GaSb direct nucleation, nanowire growth and crystal structure studies., Under de senaste 30 åren har all elektronik fått allt mindre storlek. Detta beror på att man har lyckats skala ned de komponenter som bygger upp dagens elektronik till nanoskalan. En av de allra viktigaste strukturerna som har bidragit till den här utvecklingen är nanotrådar, som är i storlek av en miljarddels meter. Nanotrådar är små avlånga strukturer som är kristallina och kan användas att bygga upp elektriska komponenter så som transistorer. Istället för att säga "framställa nanotrådar" brukar man istället använda frasen "växa nanotrådar". Det beror på att nanotråden växer nerifrån upp och väldigt ofta har en så kallad "fröpartikel", som liknar hur en växt växer. För att börja växa nanotrådar använder man oftast en metallisk fröpartikel som utgångspunkt. Beroende på vilket material partikeln består av så kan man växa olika nanotrådar vid olika temperaturer och miljöer. I mitt projekt har jag undersökt hur olika material på partikelfröet påverkar växten av nanotrådar. Nanotrådar består av halvledarmaterial vilket innebär att deras egenskaper är som en kombination av en isolator och en ledare. Det är därför halvledare är så viktiga och användbara för elektriska komponenter då deras strömledande förmåga kan kontrolleras. Atomerna i en nanotråd sitter i väldefinierade positioner som bygger upp en kristallstruktur. Man kan jämföra atomerna i kristallen med pingisbollar i en låda. Det finns flera olika sätt att placera pingisbollarna i lådan. Man kan bara slänga in dem eller lägga i dem en och en. Naturen är väldig effektiv och vill alltid minska mängden energi den ska spendera och vill fylla ut volymen på det mest effektiva sättet. Därför, enligt naturen, ska pingisbollar sättas in på det sättet som gör att vi får maximalt antal bollar i lådan. Samma princip gäller för atomerna i kristallen som strukturerar sig på så sätt att volymen fylls ut på det mest effektiva sättet. Men om man tillför energi, till exempel genom att öka temperaturen, kan atomerna börja röra på s

Corresponding author: piqueras@fis.ucm.es. This work was carried out in the frame of the European network HPRN-CT-2001-00199. Partial support of MEC (MAT2003-00455) is acknowledged. The samples were grown in the Fraunhofer Institute ISE in Freiburg. The collaboration of N. P. Barradas and M. Reis, Quaternary Ga_(1-x)In_xAs_ySb_(1-y) layers lattice matched to a GaSb substrate are of interest for applications in the infrared range. In this work, the luminescence of Ga_(1-x)In_xAs_ySb_(1-y) layers grown on GaSb by metal organic vapor phase epitaxy (MOVPE) with different In and As contents, has been studied by cathodoluminescence (CL) in a scanning electron microscope (SEM). CL images show a cellular structure which indicates the presence of dislocations decorated by recombination centers. Band gap values of 0.735 eV and 0.717 eV were measured from the CL spectra of two samples with diferent In content. This result is analyzed in the frame of existing theoretical models relating band gap with In and As content, in quaternary lattice matched layers. The band gap values are in good agreement with results of atomistic pseudopotential calculations., MEC, European network, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

© Natl Inst Optoelectronics. This work was carried out in the frame of the Fifth Framework European Programme for research; HPRN-CT 2001-00199 project. MFC acknowledges European Commission for financial support., Low band-gap InGaSb crystals are of interest for the development of thermo-photo-voltaic (TPV) cells and other devices operating in the infrared spectral range. In this work, cathodoluminescence (CL) in the scanning electron microscope (SEM) has been applied to study the homogeneity of InGaSb material grown by the vertical Bridgman technique with regard to effective incorporation of In to the ternary alloy and the nature and distribution of defects influencing the luminescence properties of this semiconductor. Back-scattered electron imaging and wavelength dispersive X-ray mapping were used as complementary techniques to CL for analysis of chemical composition and element distribution. The results show that local CL spectra provide information on the effective formation of the alloy, not revealed by other techniques., Fifth Framework European Programme for research, European Commission, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

© 1991 All Rights Reserved. This work has been supported by the DGICYT (Project No. PB93-1256) and ESP95-0148. One of the authors (P.S.D.) gratefully thanks CSIR (India) for the award of the Senior Research Fellowship and UAM, Madrid, Spain, for the visiting scientist fellowship., The homogeneity and luminescence properties of undoped bulk GaSb have been studied by the cathodoluminescence (CL) technique in the scanning electron microscope. CL images have revealed a nonuniform distribution of native defects in GaSb wafers prepared from as-grown single crystals. Postgrowth annealing in vacuum, gallium, and antimony atmospheres has been performed to obtain more accurate information about the defect structure in this material. In general, on annealing, homogeneous distribution of impurities is observed throughout the wafers. CL spectra show that a luminescence band (centered at 756 meV) is enhanced by annealing in a gallium atmosphere, suggesting that Ga atoms play an important role in the formation of this acceptor center. The 756 meV peak has been attributed to a transition from conduction band to an acceptor center comprised of Ga-Sb or a related complex. Interestingly, localized crystallization at the subgrain boundaries seems to occur by annealing in Ga atmosphere., DGICYT, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

© 2008 Elsevier Ltd. All rights reserved. International Workshop on Beam Injection Assessment of Microstructure in Semiconductors (9. 2008 -2009. Toledo, España). This work was carried out in the framework of the Fifth Framework European Programme for research, Project HPRN-CT2001-00199. Support from MCYT through Project MAT2006-01259 is also acknowledged., Cathodoluminescence (CL) in the scanning electron microscope and wavelength dispersive X-ray microanalysis (WDX) have been used to assess the homogeneity of a whole Te-doped In_xGa_(1-x)Sb ingot grown by the vertical Bridgman method under an alternating magnetic field. In particular, WDX has been used to determine the chemical composition of the ingot along the growth axis and several radial directions, while CL has been used to investigate the effective incorporation of In into the alloy, the nature and distribution of extended defects influencing the luminescence of the material and the shape evolution of the growth interfaces along the growth axis. CL spectroscopy reveals that doping with Te influences the band gap energy of this ternary compound through the Moss-Burstein effect., MCYT, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

III-V semiconductor material based nanowires have been extensively studied and shown to be a very exciting building block for future electronics. Material systems such as GaSb show a lot of promise in optoelectric and thermoelectric generation applications because of its high electron mobility and small bandgap. Although there is a lot of research about III-V nanowires, a gap in understanding antimony based nanowire growth is present. The surfactant effect of Sb makes growth of antimony based nanoowires challenging. The aim of this master thesis is to investigate direct nucleation of GaSb from both Au and Sn seed particles which would help to develop a method for direct nucleation. The study is carried out in an environmental transmission electron microscope which enables the nucleation of GaSb to be studied and recorded in-situ. Au seeded nucleation occurred at high amounts of Ga present in the particle, above 90 at.%, whilst it is shown that Sn seeded nucleation is possible for a very broad range of seed particle compositions, between 12 at.% and 70 at.%. The Au seeded nanowires were much bigger than the Sn seeded, 100 to 200 nm and 25 to 50 nm respectively, which is related to the Ga amount in the seed particle. This shows that Sn seeded GaSb direct nucleation gives much more promise if the nanowires would be integrated into electrical devices where smaller diameter nanowires are needed. For Au seeded GaSb nanowires twin planes were observed in the zinc blende crystal structure which indicated a possibility of polytypism in GaSb nanowires which has not been reported yet. The observation of polytypism in GaSb is the first step to crystal phase engineering in GaSb nanowires which could be crucial in applications such as nanowire quantum dot devices. This thesis serves as a guideline and a starting point for further GaSb direct nucleation, nanowire growth and crystal structure studies., Under de senaste 30 åren har all elektronik fått allt mindre storlek. Detta beror på att man har lyckats skala ned de komponenter som bygger upp dagens elektronik till nanoskalan. En av de allra viktigaste strukturerna som har bidragit till den här utvecklingen är nanotrådar, som är i storlek av en miljarddels meter. Nanotrådar är små avlånga strukturer som är kristallina och kan användas att bygga upp elektriska komponenter så som transistorer. Istället för att säga "framställa nanotrådar" brukar man istället använda frasen "växa nanotrådar". Det beror på att nanotråden växer nerifrån upp och väldigt ofta har en så kallad "fröpartikel", som liknar hur en växt växer. För att börja växa nanotrådar använder man oftast en metallisk fröpartikel som utgångspunkt. Beroende på vilket material partikeln består av så kan man växa olika nanotrådar vid olika temperaturer och miljöer. I mitt projekt har jag undersökt hur olika material på partikelfröet påverkar växten av nanotrådar. Nanotrådar består av halvledarmaterial vilket innebär att deras egenskaper är som en kombination av en isolator och en ledare. Det är därför halvledare är så viktiga och användbara för elektriska komponenter då deras strömledande förmåga kan kontrolleras. Atomerna i en nanotråd sitter i väldefinierade positioner som bygger upp en kristallstruktur. Man kan jämföra atomerna i kristallen med pingisbollar i en låda. Det finns flera olika sätt att placera pingisbollarna i lådan. Man kan bara slänga in dem eller lägga i dem en och en. Naturen är väldig effektiv och vill alltid minska mängden energi den ska spendera och vill fylla ut volymen på det mest effektiva sättet. Därför, enligt naturen, ska pingisbollar sättas in på det sättet som gör att vi får maximalt antal bollar i lådan. Samma princip gäller för atomerna i kristallen som strukturerar sig på så sätt att volymen fylls ut på det mest effektiva sättet. Men om man tillför energi, till exempel genom att öka temperaturen, kan atomerna börja röra på s

One of the ways to utilize III-V nanowires, is to make use of the possibility to combine materials and create heterostructures which allows for creating material combinations with new properties. A special interest can be taken into Sb-containing nanowires due to the high electron mobility, however there has been reported difficulties with switching to other materials because of a 'memory effect' where Sb lingers in the system and nanowire. Moreover, there is a need for exploring different seed materials such as Sn for nanowires since the commonly used Au can introduce problems in Si-integrated devices. In this thesis, the primary focus was to create heterostructure nanowires of Sn-seeded GaSb and GaAs and try to optimize the transitions by growing nanowires while studying them in an Environmental Transmission Electron Microscope. When growing with GaAs, a twin superlattice structure was detected at a lower V/III ratio versus at a higher V/III ratio where the nanowire grew straight zincblende. This trend seems to coincide with ex-situ work with Sn-seeded GaAs and is exciting since twins can perhaps indicate a possibility for wurtzite to form. Moreover both GaAs-GaSb and GaSb-GaAs were grown and after observing suboptimal switches, such as with substantial overgrowth or kinking, speculations were made as to why these phenomena occurred. These insights helped with the succeeding growth of GaSb-GaAs-GaAsSb heterostructures. For the GaSb-GaAs switch, the ability to switch to pure GaAs was an intriguing discovery as there has not been any record of this before. However the transitions in the GaSb-GaAs-GaAsSb heterostructure observed were gradual, and for the first switch (GaSb-GaAs) the nanowire kinked and in the second switch (GaAs-GaAsSb) As never fully left the nanowire crystal. This work has contributed to the understanding of the different roles the parameters play in terms of affecting the GaAs and GaSb heterostructure nanowire growth, but also laid a foundation fo, Kombinera halvledarmaterial på atomnivå i nanotrådar Genom att växa nanotrådar och samtidigt studera detta med supermikroskop, kan man styra kristallväxten och utveckla nya materialkombinationer för att skapa framtidens material. Så kallade nanotrådar är i en stavform där diametern är i nm-skalan medan längden kan vara i µm-skalan. Dessa nanotrådar kan vara gjorda av kristallina material och genom att skapa dem av halvledare där man kan styra över ledningsförmågan, är det av stort intresse att använda till exempelvis framtidens elektronik. Genom att kunna kombinera olika material i nanotrådar kan ytterligare applikationer upptäckas, och i detta examensarbete gjordes en övergång mellan två material (GaSb-GaAs) som enligt min vetskap aldrig gjorts förut! Ett vanligt sätt att växa nanotrådar är att använda sig av metallpartiklar som utgångspunkt, där halvledarkristallen (bestående av exempelvis Ga och As) växer från partikeln. Det kan liknas vid när ett hårstrå växer från en hårsäck - från hårsäcken samlas alla näringsämnen och delar som utgör ett hårstrå för att det sedan ska kunna växa med den färg och tjocklek som genetiken avgör. I metallpartikeln som används så kan Ga och As lösa sig i partikeln tills det blir så mycket av dem i partikeln att det är mer gynnsamt att börja bilda en halvledarkristall, se Figur 1.. Det är inte heller genetiken som avgör egenskaperna för nanotråden utan till exempel hur stor diametern på metallpartikeln är, vilka ämnen man väljer att använda, vilken temperatur som används, hur mycket av dessa ämnen Ga och As som tillförs och så vidare. Trots att det kanske låter lätt som en plätt att växa dessa nanotrådar är det snarare tvärtom. Det finns så många faktorer som influerar detta, att det är svårt att förutspå med en kristallkula exakt vad som kommer att hända. Tidigare har det ofta varit så att man växer nanotrådar som man sedan kan studera med mikroskop - men inte vilka mikroskop som helst! Istället för att använda vanliga ljusmikroskop

Quantum dots embedded in an electronic circuit allow precise control over the charge transport behaviour of the system: Charge carriers can be individually trapped or precisely shuffled between a series of quantum dots in a strictly sequential manner. This introduces ideal conditions to study fundamental quantum physics and such devices are in the focus of extensive efforts to develop quantum information related applications. This thesis contributes to the development of model systems enabling control of, and abiding by quantum mechanical effects. The aim of the model systems is to search and use advantages compared to devices governed purely by the laws of classical physics.In this thesis, transport phenomena in n- and p-type III-V semiconductor nanowire quantum dot systems are explored. First, the concepts necessary to build an understanding of charge transport across quantum dot systems, namely quantum confinement in nanostructures and Coulomb blockade, are introduced. Next, the principles of transport across single and double quantum dot devices are discussed and various experimental device designs are presented. The experimental work falls into two separate research directions and the thesis includes three published papers, which are put into context and supplemented with additional experimental results.Paper I characterizes the properties of p-type GaSb nanowires to assess the material's applicability for the realization of spin-orbit qubits as fundamental building blocks of solid state quantum computers. Experimentally, g-factors and the spin-orbit energy are determined and fabricational challenges for the realization of serial double quantum dot devices are discussed and overcome.Papers II and III study thermally driven currents in InAs nanowire double quantum dots, where heat is essentially converted to electrical power. Such nanoscale energy harvesters operate in a regime where fluctuations are highly relevant and give insights into fundamental nanothermod

El análisis de datos se presenta como una realidad en el mundo del fútbol y como una herramienta a la que acuden los profesionales del sector. Se sabe que lo más valioso y, por tanto, difícil de conseguir en Estadística, es la información. Gracias a la tecnología se pueden recoger los datos de todos los partidos de fútbol a nivel profesional cada semana obteniendo un gran volumen de información de calidad. Una vez se tienen los datos la única barrera es la imaginación, se pueden realizar análisis de todo tipo. En este trabajo se presenta un paquete de R compatible con el formato de datos de StatsBomb en el que se incluyen funciones con las que realizar análisis del juego y jugadores. El paquete GASB, creado en la realización de este TFG, cuenta con multitud de funciones gráficas para realizar representaciones sobre el terreno de juego con las que resumir ciertas acciones de juego en fútbol. El paquete GASB mezcla análisis ya utilizados en el mundo del fútbol y otros propios introducidos por el autor. Contiene funciones que permiten al usuario elegir libremente el propio el tipo de análisis que quiere realizar. Además se explica con detalle el formato de datos de StatsBomb, algunas métricas específicas del mundo del fútbol como el expected goal y posibles utilidades reales de las funciones del paquete., Data analysis is presented as a reality in the world of soccer and as a tool used by professionals in the sector. It is known that the most valuable and, therefore, difficult to obtain in Statistics, is information. Thanks to technology, data from all soccer matches can be collected at a professional level every week, obtaining a large volume of quality information. Once you have the data, you can perform all kinds of analyzes, the only barrier is your imagination. In this work, an R package compatible with the StatsBomb data format is presented, which includes functions to perform analysis of the game and players. The GASB package, created in the completion of this TFG, has a multitude of graphical functions to make representations on the field of play to summarize certain actions of the game in soccer. The GASB package mixes analyzes already used in the world of soccer and others of its own introduced by the author. It contains functions that allow the user to freely choose the type of analysis he wants to carry out. In addition, the StatsBomb data format is explained in detail, as well as some specific metrics from the world of soccer such as the expected goal and possible real utilities of the package's functions., Grado en Estadística

III-V compound Gallium Antimonide (GaSb), with a low bandgap of 0.72 eV at room temperature, is an attractive candidate for a variety of potential applications in optoelectronic devices. Ion implantation, among non-epitaxial methods, is a common and reliable doping technique to achieve local doping and obtain high-performance ohmic contacts in order to form a pn junction in such devices. An advantage of this technique over the diffusion method is the ability to perform a low-temperature process leading to accurate control of the dopant profile and avoiding Sb evaporation from GaSb surface occurring at 370 C. In this work, the effect of protons and sulfur ions as two implant species on the electrical behavior of MBE-grown undoped GaSb on semi-insulating (SI) GaAs was investigated via the Hall Effect. Protons and sulfur ions were implanted at room temperature (27 C) and 200 C, respectively, and rapid thermal annealing (RTA) was implemented at various temperatures and durations upon encapsulated GaSb. The damage induced by protons enhanced the hole density of GaSb up to around 10 times, whereas mobilities showed both increase and decrease compared to the un-implanted one, depending on the dose. While the activation of sulfur donors at an elevated temperature was anticipated after annealing sulfur implanted GaSb, instead it led to increase in p-type concentration, as the residual damage originated from sulfur implantation dominated substitutional doping. Furthermore, GaSb p/n photovoltaic devices were fabricated by applying sulfur implantation through silicon nitride layer at RT into an n-GaSb wafer (n-type base, p-type emitter). The device showed a rectifying current and photovoltaic characteristic. The J-V plot under AM1.5G illumination conditions, before and after an etch-back optimizing process, indicated lower short circuit current density J_sc, the same open circuit voltage V_oc, and higher fill factor FF, compared to the photovoltaic device with a p-type base.

El análisis de datos se presenta como una realidad en el mundo del fútbol y como una herramienta a la que acuden los profesionales del sector. Se sabe que lo más valioso y, por tanto, difícil de conseguir en Estadística, es la información. Gracias a la tecnología se pueden recoger los datos de todos los partidos de fútbol a nivel profesional cada semana obteniendo un gran volumen de información de calidad. Una vez se tienen los datos la única barrera es la imaginación, se pueden realizar análisis de todo tipo. En este trabajo se presenta un paquete de R compatible con el formato de datos de StatsBomb en el que se incluyen funciones con las que realizar análisis del juego y jugadores. El paquete GASB, creado en la realización de este TFG, cuenta con multitud de funciones gráficas para realizar representaciones sobre el terreno de juego con las que resumir ciertas acciones de juego en fútbol. El paquete GASB mezcla análisis ya utilizados en el mundo del fútbol y otros propios introducidos por el autor. Contiene funciones que permiten al usuario elegir libremente el propio el tipo de análisis que quiere realizar. Además se explica con detalle el formato de datos de StatsBomb, algunas métricas específicas del mundo del fútbol como el expected goal y posibles utilidades reales de las funciones del paquete., Data analysis is presented as a reality in the world of soccer and as a tool used by professionals in the sector. It is known that the most valuable and, therefore, difficult to obtain in Statistics, is information. Thanks to technology, data from all soccer matches can be collected at a professional level every week, obtaining a large volume of quality information. Once you have the data, you can perform all kinds of analyzes, the only barrier is your imagination. In this work, an R package compatible with the StatsBomb data format is presented, which includes functions to perform analysis of the game and players. The GASB package, created in the completion of this TFG, has a multitude of graphical functions to make representations on the field of play to summarize certain actions of the game in soccer. The GASB package mixes analyzes already used in the world of soccer and others of its own introduced by the author. It contains functions that allow the user to freely choose the type of analysis he wants to carry out. In addition, the StatsBomb data format is explained in detail, as well as some specific metrics from the world of soccer such as the expected goal and possible real utilities of the package's functions., Grado en Estadística

El análisis de datos se presenta como una realidad en el mundo del fútbol y como una herramienta a la que acuden los profesionales del sector. Se sabe que lo más valioso y, por tanto, difícil de conseguir en Estadística, es la información. Gracias a la tecnología se pueden recoger los datos de todos los partidos de fútbol a nivel profesional cada semana obteniendo un gran volumen de información de calidad. Una vez se tienen los datos la única barrera es la imaginación, se pueden realizar análisis de todo tipo. En este trabajo se presenta un paquete de R compatible con el formato de datos de StatsBomb en el que se incluyen funciones con las que realizar análisis del juego y jugadores. El paquete GASB, creado en la realización de este TFG, cuenta con multitud de funciones gráficas para realizar representaciones sobre el terreno de juego con las que resumir ciertas acciones de juego en fútbol. El paquete GASB mezcla análisis ya utilizados en el mundo del fútbol y otros propios introducidos por el autor. Contiene funciones que permiten al usuario elegir libremente el propio el tipo de análisis que quiere realizar. Además se explica con detalle el formato de datos de StatsBomb, algunas métricas específicas del mundo del fútbol como el expected goal y posibles utilidades reales de las funciones del paquete., Data analysis is presented as a reality in the world of soccer and as a tool used by professionals in the sector. It is known that the most valuable and, therefore, difficult to obtain in Statistics, is information. Thanks to technology, data from all soccer matches can be collected at a professional level every week, obtaining a large volume of quality information. Once you have the data, you can perform all kinds of analyzes, the only barrier is your imagination. In this work, an R package compatible with the StatsBomb data format is presented, which includes functions to perform analysis of the game and players. The GASB package, created in the completion of this TFG, has a multitude of graphical functions to make representations on the field of play to summarize certain actions of the game in soccer. The GASB package mixes analyzes already used in the world of soccer and others of its own introduced by the author. It contains functions that allow the user to freely choose the type of analysis he wants to carry out. In addition, the StatsBomb data format is explained in detail, as well as some specific metrics from the world of soccer such as the expected goal and possible real utilities of the package's functions., Grado en Estadística

III-V compound Gallium Antimonide (GaSb), with a low bandgap of 0.72 eV at room temperature, is an attractive candidate for a variety of potential applications in optoelectronic devices. Ion implantation, among non-epitaxial methods, is a common and reliable doping technique to achieve local doping and obtain high-performance ohmic contacts in order to form a pn junction in such devices. An advantage of this technique over the diffusion method is the ability to perform a low-temperature process leading to accurate control of the dopant profile and avoiding Sb evaporation from GaSb surface occurring at 370 C. In this work, the effect of protons and sulfur ions as two implant species on the electrical behavior of MBE-grown undoped GaSb on semi-insulating (SI) GaAs was investigated via the Hall Effect. Protons and sulfur ions were implanted at room temperature (27 C) and 200 C, respectively, and rapid thermal annealing (RTA) was implemented at various temperatures and durations upon encapsulated GaSb. The damage induced by protons enhanced the hole density of GaSb up to around 10 times, whereas mobilities showed both increase and decrease compared to the un-implanted one, depending on the dose. While the activation of sulfur donors at an elevated temperature was anticipated after annealing sulfur implanted GaSb, instead it led to increase in p-type concentration, as the residual damage originated from sulfur implantation dominated substitutional doping. Furthermore, GaSb p/n photovoltaic devices were fabricated by applying sulfur implantation through silicon nitride layer at RT into an n-GaSb wafer (n-type base, p-type emitter). The device showed a rectifying current and photovoltaic characteristic. The J-V plot under AM1.5G illumination conditions, before and after an etch-back optimizing process, indicated lower short circuit current density J_sc, the same open circuit voltage V_oc, and higher fill factor FF, compared to the photovoltaic device with a p-type base.

El análisis de datos se presenta como una realidad en el mundo del fútbol y como una herramienta a la que acuden los profesionales del sector. Se sabe que lo más valioso y, por tanto, difícil de conseguir en Estadística, es la información. Gracias a la tecnología se pueden recoger los datos de todos los partidos de fútbol a nivel profesional cada semana obteniendo un gran volumen de información de calidad. Una vez se tienen los datos la única barrera es la imaginación, se pueden realizar análisis de todo tipo. En este trabajo se presenta un paquete de R compatible con el formato de datos de StatsBomb en el que se incluyen funciones con las que realizar análisis del juego y jugadores. El paquete GASB, creado en la realización de este TFG, cuenta con multitud de funciones gráficas para realizar representaciones sobre el terreno de juego con las que resumir ciertas acciones de juego en fútbol. El paquete GASB mezcla análisis ya utilizados en el mundo del fútbol y otros propios introducidos por el autor. Contiene funciones que permiten al usuario elegir libremente el propio el tipo de análisis que quiere realizar. Además se explica con detalle el formato de datos de StatsBomb, algunas métricas específicas del mundo del fútbol como el expected goal y posibles utilidades reales de las funciones del paquete., Data analysis is presented as a reality in the world of soccer and as a tool used by professionals in the sector. It is known that the most valuable and, therefore, difficult to obtain in Statistics, is information. Thanks to technology, data from all soccer matches can be collected at a professional level every week, obtaining a large volume of quality information. Once you have the data, you can perform all kinds of analyzes, the only barrier is your imagination. In this work, an R package compatible with the StatsBomb data format is presented, which includes functions to perform analysis of the game and players. The GASB package, created in the completion of this TFG, has a multitude of graphical functions to make representations on the field of play to summarize certain actions of the game in soccer. The GASB package mixes analyzes already used in the world of soccer and others of its own introduced by the author. It contains functions that allow the user to freely choose the type of analysis he wants to carry out. In addition, the StatsBomb data format is explained in detail, as well as some specific metrics from the world of soccer such as the expected goal and possible real utilities of the package's functions., Grado en Estadística

Today, semi-conductor nanowires can be grown with very high precision, using epitaxy. This allows for studies of new nanowire-based quantum devices, likely to be part of novel quantum technologies in the future. This thesis concerns nanostructures based on InAs nanowires. More specifically, it concerns the theoretical treatment of two types of nanowire-based structures: InAs/GaSb core-shell (and core-shell-shell) nanowires, and parallel double quantum dots, made from epitaxially defined single quantum dots in InAs, confined using wurtzite barriers.For the core-shell(-shell) nanowires, we focus on the band structure of the system, using k · p theory to calculate the k-dependent energies and space dependent wave functions. We find that, for the right core and shell thicknesses, a so-called hybridization gap opens up. A hybridization gap is a band gap where conduction- and valence band-like states are inverted, but a band gap appears because of coupling between these bands. In a quantum well such an inverted band gap gives rise to topological edge states. For hollow core-shell-shell InAs/GaSb nanowires, that can be thought up as “rolled-up” quantum wells, we study the wave functions for a finite system, and establish that there are localized end-states, with energies inside the bulk gap. However, in contrast to the topological edge states in two dimensions, the end states are not robust against perturbations.We have also studied parallel double quantum dots in InAs nanowires. The double quantum dots are created by our experimental collaborators, using a new method, from a single quantum dot in a nanowire, subject to positive side gates. By tuning the side gates the interaction between the two dots formed can be tuned. The double quantum dots are investigated in collaboration with experimentalists, where they are subject to a bias voltage and an external magnetic field. The measured transport data can be very well reproduced using a few-body Hamiltonian for the dot syst

GaSb based photovoltaic devices have been demonstrated on recombination in dislocation centers is a dominant loss mechanism in GaSb solar cell grown on GaAs substrate. Also, the band offset between AlSb/GaSb is not proper for photovoltaic application and block the photogenerated carrier to reach a contact. InGaSb strained layer was chosen as replacement of AlSb defect filtering layer. Effect of strain, thickness, and a number of InGaSb defec

Gallium antimonide (GaSb) is a promising low-bandgap binary substrate for the fabrication of various infrared-based optoelectronic devices, particularly thermophotovoltaics (TPV). In order to make GaSb-based technologies like TPV more widely available, non-epitaxial dop- ing methods for GaSb must be pursued. Ion implantation is relatively unexplored for GaSb, and can offer advantages over the more common method of zinc diffusion, including higher flexibility with regards to substrate type and control over the resulting doping profile. Pre- vious work has shown beryllium (Be+) implantation to be a suitable method for fabricating a diode in an n-type GaSb substrate, opening the possibility for other ions to be considered for implanting into both n-type and p-type substrates. This work identifies sulfur (S+) as another species to investigate for this purpose. To do so, material and electrical characterization was done on S+ and beryllium implanted GaSb films grown onto a semi-insulating gallium arsenide (GaAs) substrate. X-ray Diffraction spectroscopy (XRD) and Atomic Force Microscopy (AFM) indicate that the post-implant anneal of 600 for 10 s repaired the implant damage in the bulk material, but left behind a damaged surface layer composed of coalesced vacancies. While the beryllium implant resulted in moderate doping concentrations corresponding to an activation percentage near 15 %, Hall Effect data showed that implanting S+ ions induced a strongly p-type behavior, with hole concentrations above 1 × 19 cm^3 and sheet hole densities 3.5 times higher than the total implanted dose. This strong p-type behavior is attributed to the remaining lattice damage caused by the implant, which induces a large density of acceptor-like defect states near the valence band edge. This technique was used on an unintentionally-doped p-type GaSb substrate to create a + /p junction. The implant process succeeded in producing a potential barrier similar to that of a hole-majority camel dio

GaSb based photovoltaic devices have been demonstrated on recombination in dislocation centers is a dominant loss mechanism in GaSb solar cell grown on GaAs substrate. Also, the band offset between AlSb/GaSb is not proper for photovoltaic application and block the photogenerated carrier to reach a contact. InGaSb strained layer was chosen as replacement of AlSb defect filtering layer. Effect of strain, thickness, and a number of InGaSb defec

Two approaches to integrate GaSb onto silicon were investigated: interfacial misfit growth of GaSb on GaAs-on-Si templates and GaSb-on-V-grooved Si using the aspect ratio trapping technique. GaSb thin films grown on both substrates were found to be highly relaxed and have comparable crystalline quality. The primary defect generation mechanism in both samples was investigated and discussed. © 2018 GaAs Mantech Incorporated. All Rights Reserved.

Two approaches to integrate GaSb onto silicon were investigated: interfacial misfit growth of GaSb on GaAs-on-Si templates and GaSb-on-V-grooved Si using the aspect ratio trapping technique. GaSb thin films grown on both substrates were found to be highly relaxed and have comparable crystalline quality. The primary defect generation mechanism in both samples was investigated and discussed. © 2018 GaAs Mantech Incorporated. All Rights Reserved.

Single nanowire transistors employing three separately controlled electrostatic gates were fabricated to investigate band gap modulation in InAs-GaSb heterostructures. The aim is to show hybridization between electron and hole states over the heterojunction. Electric and thermoelectric characterization at low temperatures suggests that transport can be tuned from electrons in InAs to holes GaSb and that the relative band alignment can be altered from an inverted to a small effective gap. The band gap modulation is speculated to be caused by quantum confinement induced by the gates.

Single nanowire transistors employing three separately controlled electrostatic gates were fabricated to investigate band gap modulation in InAs-GaSb heterostructures. The aim is to show hybridization between electron and hole states over the heterojunction. Electric and thermoelectric characterization at low temperatures suggests that transport can be tuned from electrons in InAs to holes GaSb and that the relative band alignment can be altered from an inverted to a small effective gap. The band gap modulation is speculated to be caused by quantum confinement induced by the gates.

Two approaches to integrate GaSb onto silicon were investigated: interfacial misfit growth of GaSb on GaAs-on-Si templates and GaSb-on-V-grooved Si using the aspect ratio trapping technique. GaSb thin films grown on both substrates were found to be highly relaxed and have comparable crystalline quality. The primary defect generation mechanism in both samples was investigated and discussed. © 2018 GaAs Mantech Incorporated. All Rights Reserved.

We present experimental data from vertical InAs/InGaAsSb/GaSb nanowire tunnel field-effect transistors with channel diameter scaled down to 10 nm and ability to reach a point subthreshold swing of 35 mV/decade at VDS = 0.05 V. Furthermore, the impact of drain, channel and source diameter scaling on the subthreshold swing and currents are studied. Impact of gate-overlap is more evident for devices with highly scaled source due to strong reduction of the current. Furthermore, small channel diameter makes these devices more susceptible to Random Telegraph Signal noise.

GaSb Thermophotovoltaics are a key technology in the search for the ability to power small scale autonomous systems. In this work, MBE grown GaSb photovoltaic devices are fabricated and tested under AM 1.5 conditions. These devices displayed short circuit current values as high as 40 mA/cm2 but were found to have poor series resistance. The parasitic resistive characteristics were factored out of the measured cell data and it was found that the photocurrent for the fabricated devices could be as much as 6 mA/cm2 higher then the measured short circuit current. An additional layer of metal was added to the reduce the deleterious resistance characteristics, and it was found to lower the series resistance down to a 4 Ω average across almost all of the devices. The average JSC for all of these devices increased to over 30 mA/cm2, with highs well over 40 mA/cm2, a more consistent result than the original single metal deposition devices. Graphene was applied to the originally fabricated devices in an attempt to remove the series resistances issues as well as act as a surface passivation layer. The graphene was able to reduce series resistance by as much as 50% on some of the devices, with a corresponding 6 mA/cm2 increase in short circuit current exhibited. The photocurrent and diode current values were not changed by more than a measurement error, an indication that surface passivaiton may not have taken place. Graphene was a suitable approach for solving the series resistance issue and its use as both a transparent conductive layer and surface passivation material deserve further investigation.

Physical characteristics: Original contains illustrations, 形態: 図版あり, Accepted: 2016-12-13

With the constant downscaling of Si transistors reaching its limits, other alternatives have been actively researched the past decades. Group III-V semiconductors are excellent materials with generally high carrier mobilities that can replace Si in transistors. Strain has been used for some years to improve silicon technology, and it can also be applied to III-V materials to make them perform even better. In this work, GaSb nanowire transistors were strained using PECVD to deposit a stressing film of Si3N4 and the effects on the electrical characteristics investigated. The deposited films ranged between thicknesses of 40-104 nm, with stresses in the range 300-2000 MPa. Raman spectroscopy measurements showed a strain in the nanowires up to 0.5%. The effect on the threshold voltage from the Si3N4 films containing positive charges made it challenging to separate the effects from this and the effects from strain. All samples exhibited a reduction in current but a signicant increase in the on/off-ratio, making the strained devices turn off much better than untreated devices, with an on/off-ratio increase of up to 70 times observed. The results obtained here show that this method of process induced strain could see uses in order to reduce power consumption., “Om bilar hade utvecklats lika snabbt som datorprocessorer skulle de köra i 760 000 km/h, köra 100 km på enbart 2.4 ml bensin, och kosta 30 öre” hävdar Paul Ottelini, tidigare VD för Intel som är planetens största utvecklare och tillverkare av processorer. En processor är den enhet i din dator eller telefon som utför alla instruktioner och beräkningar som program kräver. Processorer idag innehåller flera miljarder transistorer, som är den viktigaste byggstenen i de flesta elektroniska komponenter. Det är en makalös prestation som gjorts inom utvecklingen av transistorer de senaste 50 åren som lett till den prestanda vår teknologi har idag. En transistor uppför sig som en lampknapp, som antingen kan slås av eller på mer är en miljard gånger per sekund. Genom att kombinera transistorer som är antingen av eller på kan processorn utföra komplicerade beräkningar snabbt. Transistorer har sedan länge varit tillverkade av kisel, vilket är ett ämne med bra elektriska egenskaper, men det har främst blivit använt tack vare dess rikliga tillgång på jorden, eftersom det utvinns från sand, vilket även gör kisel väldigt billigt. Utvecklingen av transistorer har mest skett genom att minska storleken på dem vilket gör dem snabbare, men de är numera så pass små att detta inte är möjligt. Därför sker det mycket forskning kring andra ämnen som kan ersätta kisel, eller att hitta andra metoder som kan förbättra transistorerna. En sådan metod som använts i flera år på kiselprodukter är att belasta transistorerna så de trycks ihop. Det har visat sig att om ett ämne som kisel trycks ihop så att atomerna hamnar närmre varandra, kan dess elektriska egenskaper förbättras avsevärt. I det här arbetet har denna teknik använts på nanotrådar av galliumantimonid. En nanotråd är ett trådformat objekt så litet att det skulle behöva ligga flera miljoner trådar intill varandra för att du skulle kunna upptäcka dem med blotta ögat. Galliumantimonid är ett av de ämnen som kisel kan bytas mot, det är dock m, "If cars had developed as fast as computer processors they would go at 760 000 km/h, drive 100 km on only 2.4 ml gas, and cost 3 cents" claims Paul Ottelini, former CEO of Intel which is the world leading developer and manufacturer of processors. A processor is the unit in your phone or computer that performs all the instructions or calculations that programs require. Processors today consist of billions of transistors, which is the most important building block in most electronic components. It is an amazing accomplishment that's been done in the development of transistors over the past 50 years that has led to the performance of our technology today. A transistor behaves as a switch, that can be turned either on or off more than a billion times per second. By combining transistors that are turned on or off, the processor can perform complicated tasks fast. Transistors have since long been made out of silicon, which is a material with good electrical properties, but it has mainly been used due to its ample availability on earth, since it is extracted from sand, which also makes silicon very cheap. The development of transistors has mostly been done by reducing their size which makes them faster, but they are now so small that this is no longer possible. Therefore, much research is taking place around other materials that could replace silicon, or finding other methods that can enhance transistors further. One such method that has been used on the market for some years now is straining the silicon in transistors. It has been found that by straining a material so that its atoms are closer together or further apart can considerably improve its electrical properties. In this work, strain has been used on nanowires of gallium antimonide. A nanowire is a wireshaped object so small that it would require a million adjacent wires to be spotted with the naked eye. Gallium antimonide is one of the materials that could replace silicon, although it is much more expensive. The n

With the constant downscaling of Si transistors reaching its limits, other alternatives have been actively researched the past decades. Group III-V semiconductors are excellent materials with generally high carrier mobilities that can replace Si in transistors. Strain has been used for some years to improve silicon technology, and it can also be applied to III-V materials to make them perform even better. In this work, GaSb nanowire transistors were strained using PECVD to deposit a stressing film of Si3N4 and the effects on the electrical characteristics investigated. The deposited films ranged between thicknesses of 40-104 nm, with stresses in the range 300-2000 MPa. Raman spectroscopy measurements showed a strain in the nanowires up to 0.5%. The effect on the threshold voltage from the Si3N4 films containing positive charges made it challenging to separate the effects from this and the effects from strain. All samples exhibited a reduction in current but a signicant increase in the on/off-ratio, making the strained devices turn off much better than untreated devices, with an on/off-ratio increase of up to 70 times observed. The results obtained here show that this method of process induced strain could see uses in order to reduce power consumption., “Om bilar hade utvecklats lika snabbt som datorprocessorer skulle de köra i 760 000 km/h, köra 100 km på enbart 2.4 ml bensin, och kosta 30 öre” hävdar Paul Ottelini, tidigare VD för Intel som är planetens största utvecklare och tillverkare av processorer. En processor är den enhet i din dator eller telefon som utför alla instruktioner och beräkningar som program kräver. Processorer idag innehåller flera miljarder transistorer, som är den viktigaste byggstenen i de flesta elektroniska komponenter. Det är en makalös prestation som gjorts inom utvecklingen av transistorer de senaste 50 åren som lett till den prestanda vår teknologi har idag. En transistor uppför sig som en lampknapp, som antingen kan slås av eller på mer är en miljard gånger per sekund. Genom att kombinera transistorer som är antingen av eller på kan processorn utföra komplicerade beräkningar snabbt. Transistorer har sedan länge varit tillverkade av kisel, vilket är ett ämne med bra elektriska egenskaper, men det har främst blivit använt tack vare dess rikliga tillgång på jorden, eftersom det utvinns från sand, vilket även gör kisel väldigt billigt. Utvecklingen av transistorer har mest skett genom att minska storleken på dem vilket gör dem snabbare, men de är numera så pass små att detta inte är möjligt. Därför sker det mycket forskning kring andra ämnen som kan ersätta kisel, eller att hitta andra metoder som kan förbättra transistorerna. En sådan metod som använts i flera år på kiselprodukter är att belasta transistorerna så de trycks ihop. Det har visat sig att om ett ämne som kisel trycks ihop så att atomerna hamnar närmre varandra, kan dess elektriska egenskaper förbättras avsevärt. I det här arbetet har denna teknik använts på nanotrådar av galliumantimonid. En nanotråd är ett trådformat objekt så litet att det skulle behöva ligga flera miljoner trådar intill varandra för att du skulle kunna upptäcka dem med blotta ögat. Galliumantimonid är ett av de ämnen som kisel kan bytas mot, det är dock m, "If cars had developed as fast as computer processors they would go at 760 000 km/h, drive 100 km on only 2.4 ml gas, and cost 3 cents" claims Paul Ottelini, former CEO of Intel which is the world leading developer and manufacturer of processors. A processor is the unit in your phone or computer that performs all the instructions or calculations that programs require. Processors today consist of billions of transistors, which is the most important building block in most electronic components. It is an amazing accomplishment that's been done in the development of transistors over the past 50 years that has led to the performance of our technology today. A transistor behaves as a switch, that can be turned either on or off more than a billion times per second. By combining transistors that are turned on or off, the processor can perform complicated tasks fast. Transistors have since long been made out of silicon, which is a material with good electrical properties, but it has mainly been used due to its ample availability on earth, since it is extracted from sand, which also makes silicon very cheap. The development of transistors has mostly been done by reducing their size which makes them faster, but they are now so small that this is no longer possible. Therefore, much research is taking place around other materials that could replace silicon, or finding other methods that can enhance transistors further. One such method that has been used on the market for some years now is straining the silicon in transistors. It has been found that by straining a material so that its atoms are closer together or further apart can considerably improve its electrical properties. In this work, strain has been used on nanowires of gallium antimonide. A nanowire is a wireshaped object so small that it would require a million adjacent wires to be spotted with the naked eye. Gallium antimonide is one of the materials that could replace silicon, although it is much more expensive. The n

Tunneling field-effect transistors (TunnelFET), a leading steep-slope transistor candidate, is still plagued by defect response, and there is a large discrepancy between measured and simulated device performance. In this work, highly scaled InAs/InxGa1−xAsySb1‑y/GaSb vertical nanowire TunnelFET with ability to operate well below 60 mV/decade at technically relevant currents are fabricated and characterized. The structure, composition, and strain is characterized usingtransmission electron microscopy with emphasis on the heterojunction. Using Technology Computer Aided Design (TCAD) simulations and Random Telegraph Signal (RTS) noise measurements, effects of different type of defects are studied. The study reveals that the bulk defects have the largest impact on the performance of these devices, although for these highly scaled devices interaction with even few oxide defects can have large impact on the performance. Understanding the contribution by individual defects, as outlined in this letter, is essential to verify the fundamental physics of device operation, and thus imperative for taking the III−V TunnelFETs to the next level.

The growth of GaSb on GaAs is of interest for a variety of scientific and technological applications. Some evidence suggests that low threading dislocation density GaSb can be grown directly on GaAs through arrays of periodic edge misfit dislocations. However, significant conflicting data also exist. This work seeks to clarify the question through transmission electron microscopy analysis of GaSb grown on GaAs. The results of this work show that the single strategy of direct growth of GaSb on GaAs results in dislocation densities too high for devices. A secondary strategy of dislocation filtering layers is introduced to further reduce threading dislocations. Dislocation filtering layers are shown to be effective at bending threading dislocations at strained interfaces. Advanced analytical methods are employed to assist in developing a unique view of the dislocation filtering layer. These results enable a comprehensive evaluation of dislocation behavior extending the scientific understanding of this complex interface.

Nanowire tunnel field-effect transistors (TFETs) were investigated by carrying out noise measurements and low-temperature DC measurements. The TFET tunnelling junction was realised by a GaSb/InAs heterojunction resulting in a broken band gap. TFET noise currents were measured at frequencies between 10 Hz and 1 kHz. The results imply that noise in TFETs at the current state of development is dominated by generation-recombination processes caused by traps in the gate oxide. Trap densities between 10^20 cm^-3 eV^-1 and 10^22 cm^-3 eV^-1 were extracted from the noise measurements. The temperature-dependent DC measurements show that the TFETs' off-current is sensitive to the temperature, with lower off-currents at lower temperatures. This indicates that it is not only the tunnelling junction which is governing the off-current. It is concluded that in the devices' off-state electrons can still tunnel into the channel area through the broken band gap but require additional thermionic excitation over the bent channel conduction band to constitute a current., The ever-growing demand for electronic devices in all areas of our lives can only be satisfied due to the constant development of today’s most essential of all active electronic devices – the metal-oxide-semiconductor field-effect transistor (MOSFET). However, its further development is drawing to an end, so coming up with alternatives is of utmost importance. One of the most promising ones is the tunnel field-effect transistor (TFET). A MOSFET basically is an electrical switch. The current between two of the device’s contacts – source and drain – can be controlled by a third contact, the gate. In digital applications, such as all our computers and smartphones, MOSFETs only switch between an on- and an off-state, meaning flowing current or almost no current, respectively. The ability to switch between these two states as fast as possible is what governs a MOSFET’s speed and energy-efficiency. Over the last 50 years MOSFETs have undergone constant development to increase these measures. Due to the underlying physical principles that MOSFETs are based on, this development is drawing to an end. In a MOSFET electrons have to overcome an energy barrier to establish a current. With the gate contact this barrier can be raised (off-state) or lowered (on-state). This principle establishing the current is at the same time the principle which limits further scaling of MOSFETs as there are always a few electrons which can overcome the barrier – even in the device’s off-state. The idea for TFETs to overcome this limit is to control the current by opening or closing a narrow gap in the energy structure of the device. Instead of overcoming a barrier the electrons have to tunnel through it. In contrast to the MOSFET structure the electrons on the source side of the TFET structure face a restriction from the top which reduces the off-current. In my thesis I contribute to the development of TFETs as successors of or complements to MOSFETs by examining electrical noise and the current

Nanowire tunnel field-effect transistors (TFETs) were investigated by carrying out noise measurements and low-temperature DC measurements. The TFET tunnelling junction was realised by a GaSb/InAs heterojunction resulting in a broken band gap. TFET noise currents were measured at frequencies between 10 Hz and 1 kHz. The results imply that noise in TFETs at the current state of development is dominated by generation-recombination processes caused by traps in the gate oxide. Trap densities between 10^20 cm^-3 eV^-1 and 10^22 cm^-3 eV^-1 were extracted from the noise measurements. The temperature-dependent DC measurements show that the TFETs' off-current is sensitive to the temperature, with lower off-currents at lower temperatures. This indicates that it is not only the tunnelling junction which is governing the off-current. It is concluded that in the devices' off-state electrons can still tunnel into the channel area through the broken band gap but require additional thermionic excitation over the bent channel conduction band to constitute a current., The ever-growing demand for electronic devices in all areas of our lives can only be satisfied due to the constant development of today’s most essential of all active electronic devices – the metal-oxide-semiconductor field-effect transistor (MOSFET). However, its further development is drawing to an end, so coming up with alternatives is of utmost importance. One of the most promising ones is the tunnel field-effect transistor (TFET). A MOSFET basically is an electrical switch. The current between two of the device’s contacts – source and drain – can be controlled by a third contact, the gate. In digital applications, such as all our computers and smartphones, MOSFETs only switch between an on- and an off-state, meaning flowing current or almost no current, respectively. The ability to switch between these two states as fast as possible is what governs a MOSFET’s speed and energy-efficiency. Over the last 50 years MOSFETs have undergone constant development to increase these measures. Due to the underlying physical principles that MOSFETs are based on, this development is drawing to an end. In a MOSFET electrons have to overcome an energy barrier to establish a current. With the gate contact this barrier can be raised (off-state) or lowered (on-state). This principle establishing the current is at the same time the principle which limits further scaling of MOSFETs as there are always a few electrons which can overcome the barrier – even in the device’s off-state. The idea for TFETs to overcome this limit is to control the current by opening or closing a narrow gap in the energy structure of the device. Instead of overcoming a barrier the electrons have to tunnel through it. In contrast to the MOSFET structure the electrons on the source side of the TFET structure face a restriction from the top which reduces the off-current. In my thesis I contribute to the development of TFETs as successors of or complements to MOSFETs by examining electrical noise and the current

III-V semiconductors have attractive transport properties suitable for low-power, high-speed complementary metal oxide-semiconductor (CMOS) implementation, but major challenges related to cointegration of III-V n- and p-type metal-oxide-semiconductor field-effect transistors (MOSFETs) on low-cost Si substrates have so far hindered their use for large scale logic circuits. By using a novel approach to grow both InAs and InAs/GaSb vertical nanowires of equal length simultaneously in one single growth step, we here demonstrate n- and p-type III-V MOSFETs monolithically integrated on a Si substrate with high I-on/I-off ratios using a dual channel, single gate-stack design processed simultaneously for both types of transistors. In addition, we demonstrate fundamental CMOS logic gates, such as inverters and NAND gates, which illustrate the viability of our approach for large scale III-V MOSFET circuits on Si.

Quantum dots, due to their small size, portray unique optical properties that are different compared to those of the bulk material. The most apparent of these properties is the excitation of these dots, resulting in emission of photons, which are visible to the human eye as light. More interestingly, the wavelength of these photon emissions does not solely depend on the type of material from which the quantum dot is made; in addition, it depends on the size of the quantum dots. The dots can also be tuned accordingly to emit into the UV or into the infra-red. The colloidal synthesis of CdSe/ZnS quantum dots is presented, to describe their incorporation into nanovoids formed on GaSb membranes. Nanoscale etch-pit formation on GaSb surfaces happens as a result of arsenic (As2) based in situ etch technique. The effect of in situ etch technique leading to the formation of the nanovoids was studied. Atomic force microscopy, scanning electron microscope, and transmission electron microscopy were used to characterize the GaSb surface, to investigate the internal structure of the voids, and to determine the average size dimensions of the voids, and the void density. Furthermore, experiments and measurements were carried out to check the ability of the quantum dots to fluoresce at the high regrowth temperatures inside the molecular beam epitaxy system. CdSe/ZnS quantum dots were used, considering their high stability over time. The quantum dots were further annealed at different temperatures, and optically characterized to investigate if the core-shell structure changed as a result of the high temperature. Encapsulation of these quantum dots into the highly faceted nanovoids offer potential applications for quantum-confined ensembles.

Infrared detectors based on compound semiconductor technology are on the verge of outperforming HgCdTe, the leading infrared material for the past 50 years. The driving force behind this change has been the development of new detector designs based on the 6.1 � lattice constant, which includes GaSb, AlSb, and InAs binary materials. While the epitaxial deposition of these materials on GaSb substrates has enabled high performance devices, key limitations still exist. The lack of a large diameter, semi-insulating substrate; a mature, ohmic n-contact to GaSb; and a low k, large bandgap material for avalanche multiplication are all key weaknesses of this material system that further limit device development.These challenges can be met by the introduction of a new epitaxial growth mode. The growth mode, an interfacial misfit array (IMF), enables the epitaxial deposition of a high quality, relaxed GaSb epilayer on a GaAs substrate without the creation of residual threading dislocations. The IMF achieves this feat through the creation of a 90� dislocation network at the GaSb/GaAs interface, i.e. a gallium dangling bond every 14 GaAs lattice sites.In this dissertation, the structural, electrical, and optical characterization of IMF-based material and devices are all described. X-ray diffraction experiments are used to show that the dislocation network is nearly perfectly correlated, i.e. there is a 99% correlation between the location of one Lomer dislocation in the IMF network and its adjacent dislocations. Further evidence is given that the material is over 99.5% relaxed after 250 nm of growth, and continues to relax as the GaSb epilayer becomes thicker. Optical RF measurements of GaSb p-i-n homojunctions on GaAs semi-insulating substrates show that the IMF is capable of passing high frequency signals, and that the background acceptor concentration can be reduced to approximately 2 x 1016 cm-3 using Tellurium compensation doping. C-V profiles of one-sided GaAs junction

The III-V semiconducting compounds InAs and GaSb were studied using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). Different crystal planes of each material were investigated separately, including wafers of InAs(111)A, InAs(111)B, InAs(110), GaSb(100), GaSb(110) as well as nanowires consisting of InAs. All these materials were imaged both before and after exposure to atomic hydrogen along with moderate annealing in order to compare and characterize changes of the surface morphology. Generally, a high success rate for cleaning with atomic hydrogen was established, with atomic resolution achieved for InAs(111)A, InAs(110), GaSb(100) and the nanowires. Conclusions regarding reconstructions of the surfaces were made from STM measurements, and regarding remnant oxides and the efficiency of the cleaning recipes from XPS data.

Infrared detectors based on compound semiconductor technology are on the verge of outperforming HgCdTe, the leading infrared material for the past 50 years. The driving force behind this change has been the development of new detector designs based on the 6.1 � lattice constant, which includes GaSb, AlSb, and InAs binary materials. While the epitaxial deposition of these materials on GaSb substrates has enabled high performance devices, key limitations still exist. The lack of a large diameter, semi-insulating substrate; a mature, ohmic n-contact to GaSb; and a low k, large bandgap material for avalanche multiplication are all key weaknesses of this material system that further limit device development.These challenges can be met by the introduction of a new epitaxial growth mode. The growth mode, an interfacial misfit array (IMF), enables the epitaxial deposition of a high quality, relaxed GaSb epilayer on a GaAs substrate without the creation of residual threading dislocations. The IMF achieves this feat through the creation of a 90� dislocation network at the GaSb/GaAs interface, i.e. a gallium dangling bond every 14 GaAs lattice sites.In this dissertation, the structural, electrical, and optical characterization of IMF-based material and devices are all described. X-ray diffraction experiments are used to show that the dislocation network is nearly perfectly correlated, i.e. there is a 99% correlation between the location of one Lomer dislocation in the IMF network and its adjacent dislocations. Further evidence is given that the material is over 99.5% relaxed after 250 nm of growth, and continues to relax as the GaSb epilayer becomes thicker. Optical RF measurements of GaSb p-i-n homojunctions on GaAs semi-insulating substrates show that the IMF is capable of passing high frequency signals, and that the background acceptor concentration can be reduced to approximately 2 x 1016 cm-3 using Tellurium compensation doping. C-V profiles of one-sided GaAs junction

The III-V semiconducting compounds InAs and GaSb were studied using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). Different crystal planes of each material were investigated separately, including wafers of InAs(111)A, InAs(111)B, InAs(110), GaSb(100), GaSb(110) as well as nanowires consisting of InAs. All these materials were imaged both before and after exposure to atomic hydrogen along with moderate annealing in order to compare and characterize changes of the surface morphology. Generally, a high success rate for cleaning with atomic hydrogen was established, with atomic resolution achieved for InAs(111)A, InAs(110), GaSb(100) and the nanowires. Conclusions regarding reconstructions of the surfaces were made from STM measurements, and regarding remnant oxides and the efficiency of the cleaning recipes from XPS data.

Blueshifts of luminescence observed in type-II heterostructures are quantitatively examined in terms of a self-consistent approach including excitonic effects. This analysis shows that the main contribution to the blueshift originates from the well region rather than the variation of triangular potentials formed in the barrier region. The power law for the blueshift, ΔEPL ∝ Plaserm, from m = 1/2 for lower excitation Plaser to m = 1/4 for higher excitation, is obtained from the calculated results combined with a rate equation analysis, which also covers the previously believed m = 1/3 power law within a limited excitation range. The present power law is consistent with the blueshift observed in a GaAsSb/GaAs quantum well.

The crystal quality and structural properties of GaSb thin films grown on a semi-insulator GaAs (001) substrate by metalorganic chemical vapor deposition (MOCVD) using triethylgallium and trimethylantimony were characterized by high-resolution X-ray diffraction and high-resolution transmission electron microscopy. The nucleation of the interfacial misfit dislocations (IMF) array in the GaSb/GaAs interface, which is dependent on the antimony ambience, was investigated by varying the V/III ratio. Our experiment results showed that the IMF array and threading dislocation density are modified in the GaSb epilayer with different antimony ambiences. The GaSb thin film grown by the IMF mode on GaAs was confirmed under our optimal growth condition, and the hole density and mobility of GaSb thin films were found to be 5.27 x 10l6 cm(-3) (1.20 x 10l6) and 553 cm(2)/V-s (2340) at RT (77 K) from Hall measurements. We suggest that the IMF growth mode can also be applied to fabricate the GaSb film on GaAs by MOCVD for application in microelectronic devices.

The crystal quality and structural properties of GaSb thin films grown on a semi-insulator GaAs (001) substrate by metalorganic chemical vapor deposition (MOCVD) using triethylgallium and trimethylantimony were characterized by high-resolution X-ray diffraction and high-resolution transmission electron microscopy. The nucleation of the interfacial misfit dislocations (IMF) array in the GaSb/GaAs interface, which is dependent on the antimony ambience, was investigated by varying the V/III ratio. Our experiment results showed that the IMF array and threading dislocation density are modified in the GaSb epilayer with different antimony ambiences. The GaSb thin film grown by the IMF mode on GaAs was confirmed under our optimal growth condition, and the hole density and mobility of GaSb thin films were found to be 5.27 x 10l6 cm(-3) (1.20 x 10l6) and 553 cm(2)/V-s (2340) at RT (77 K) from Hall measurements. We suggest that the IMF growth mode can also be applied to fabricate the GaSb film on GaAs by MOCVD for application in microelectronic devices.