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Black titania nanotubes possess an extraordinary surface functionality while having a high absorbance in the visible light range. In this study, a low-temperature manufacturing approach for dark titania nanotubes is presented: low-energy low-fluence carbon ion implantation. It allows a local chemical reduction, preserves the amorphous structure and induces oxygen vacancies, leading to high electrical conductivity. The material's modification is unveiled on microscopic and macroscopic scales: electrical characteristics are recorded on the nanometer scale using tunneling atomic force microscopy and overall with two-point measurements. The depth-resolved atomic composition is assessed via elastic recoil detection analysis, while optical and x-ray photoelectron spectroscopy elucidate the global chemical binding situation and bandgap shifts. This extensive analysis supports the concept of percolated carbon paths that vertically span the nanotubes and provide a substantial contribution to the enhanced conductivity. In combination with the utilization of implantation masks, a versatile route for a targeted and localized material's manipulation toward patterned dark amorphous titania nanotubes is demonstrated that gives rise to innovative materials and smart devices. [ABSTRACT FROM AUTHOR]

Defects tend to modify significantly the properties of semiconductors, such as transport properties, by increasing the scattering of electrons and phonons, or optical properties, by modifying the band structure and the Fermi level. The high interest of ScN thin films for thermoelectric applications results from the incorporation of oxygen, which is well known to be the source for their degenerate n-type state and their significant power factor. Indeed, oxygen acts as a donor defect when substituted to nitrogen. In this study, oxygen ion implantation was performed at a high damage level as a way to modify electrical properties through defect engineering. Hence, we measured the changes in electrical properties induced by oxygen implantation at room temperature. Two types of defects have been identified as being responsible for the change in resistivity, carrier concentration, mobility, and Seebeck coefficient. At first, the point-like defects, recombining from 440 K and onward, introduce localized states near the Fermi level, inducing a change in the conduction mode from a metallic-like to a hopping mechanism. The relationship between Mott's temperature and defect concentration has been clearly demonstrated through in situ resistivity measurements in the 80–750 K temperature range. Furthermore, these measurements highlight that oxygen induced defects result not only from ballistic effects, but also from chemical effects that are involved. Second, the complex-like defects introduce deep acceptor levels into the bandgap and act as scattering centers that modify the Debye temperature as well as the electron–phonon interactions. These complexes, likely between scandium vacancies and oxygen atoms (VSc-yO, y ≤ 4), are primarily responsible for the increase of the Seebeck coefficient and the reduced mobility. The concentration of such defects can qualitatively be assessed as their formation introduces an additional term, independent of temperature, in the variation of resistivity, mobility, and also the Seebeck coefficient. The recovery of the complex-like defects takes place at a minimum temperature of 750 K. Results show that the effectiveness of oxygen in creating defects exceeds that of noble gases in terms of concentration, demonstrating the promise of this approach to control the electrical properties of ScN. [ABSTRACT FROM AUTHOR]

The peculiarities and modes of material modification with high-intensity, high-power density ion beams on the irradiated surface are studied for the first time. Chromium ions are implanted into a zirconium alloy using a 25 kW/cm2, 450 μs beam at the pulse repetition rates within 8–35 pps. Every high-energy ion pulse impact is followed by ultrafast cooling of the surface due to heat removal into the target material. Three modes are studied at the temperatures of 580, 700, and 900 °C with an additional pulsed heating. An increase in the average target temperature from 580 to 700 °C within 1 h at the same pulse power density allows increasing the depth of chromium ion alloying from 1.5 to more than 7 μm. The use of ultrafast cooling of the Zr1%Nb alloy surface offers a grain size reduction from a few μm to approximately 50–250 nm, without any microstructural changes throughout the sample volume. An inhomogeneous chromium ion distribution over the target surface and depth is observed. [ABSTRACT FROM AUTHOR]

The semiconductor industry is a resource-intensive sector that heavily relies on energy, water, chemicals, and raw materials. Within the semiconductor manufacturing process, the diffusion furnace, ion implantation machine, and plasma etching machine exhibit high energy demands or operate at extremely high temperatures, resulting in significant electricity consumption, which is usually carbon-intensive. To address energy conservation concerns, the industry adopts batch production technology, which allows for the simultaneous processing of multiple products. The energy-efficient parallel batch scheduling problem arises from the need to optimise product grouping and sequencing. In contrast to existing heuristics, meta-heuristics, and exact algorithms, this paper introduces the Deep Q-Network (DQN) algorithm as a novel approach to address the proposed problem. The DQN algorithm is built upon the agent's systematic learning of scheduling rules, thereby enabling it to offer guidance for online decision-making regarding the grouping and sequencing of products. The efficacy of the algorithm is substantiated through extensive computational experiments. [ABSTRACT FROM AUTHOR]

For many years, Si1−yGey alloys have been applied in the semiconductor industry due to the ability to adjust the performance of Si-based nanoelectronic devices. Following this alloying approach of group-IV semiconductors, adding tin (Sn) into the alloy appears as the obvious next step, which leads to additional possibilities for tailoring the material properties. Adding Sn enables effective bandgap and strain engineering and can improve the carrier mobilities, which makes Si1−x−yGeySnx alloys promising candidates for future opto- and nanoelectronics applications. The bottom-up approach for epitaxial growth of Si1−x−yGeySnx, e.g., by chemical vapor deposition and molecular beam epitaxy, allows tuning the material properties in the growth direction only; the realization of local material modifications to generate lateral heterostructures with such a bottom-up approach is extremely elaborate, since it would require the use of lithography, etching, and either selective epitaxy or epitaxy and chemical–mechanical polishing, giving rise to interface issues, non-planar substrates, etc. This article shows the possibility of fabricating Si1−x−yGeySnx alloys by Sn ion beam implantation into Si1−yGey layers followed by millisecond-range flash lamp annealing (FLA). The materials are investigated by Rutherford backscattering spectrometry, micro-Raman spectroscopy, x-ray diffraction, and transmission electron microscopy. The fabrication approach was adapted to ultra-thin Si1−yGey layers on silicon-on-insulator substrates. The results show the fabrication of single-crystalline Si1−x−yGeySnx with up to 2.3 at. % incorporated Sn without any indication of Sn segregation after recrystallization via FLA. Finally, we exhibit the possibility of implanting Sn locally in ultra-thin Si1−yGey films by masking unstructured regions on the chip, thus demonstrating the realization of vertical as well as lateral Si1−x−yGeySnx heterostructures by Sn ion implantation and flash lamp annealing. [ABSTRACT FROM AUTHOR]

Photo modulated optical reflectance (PMOR) is an ideal ultra-shallow junction area metrology technique for measurement of transistor dopant distribution in integrated circuit fabrication, and the characterization of process parameters such as implant energy, implant angle, and implant dose has a significant impact on the accuracy of the ion implantation process. This study utilized deep learning to analyze various process parameters concurrently and assessed its performance on boron-doped silicon samples, the data were obtained from the power curves measured from Carrier Illumination (CI) experiments in PMOR, a deep learning model with multi-task learning architecture was developed and trained to characterize multiple process parameters, and the PMOR model incorporating a multi-task learning architecture for process parameters demonstrated superior performance in terms of accuracy and speed of characterization. The analyses indicated that applying deep learning methods to CI metrology in PMOR technology is feasible. In particular, compared with the conventional carrier irradiation technique, the ability to obtain the implantation dose and doping profile along with other process parameters such as implantation energy, implantation angle, and implantation type can better assist in the accurate realization of the ion implantation process with acceptable accuracy and time cost. [ABSTRACT FROM AUTHOR]

An area-selectable Mg doping via ion implantation (I/I) is essential to realize gallium nitride (GaN) based power switching devices. Conventional post-implantation annealing forms considerable defects in the GaN, resulting in extremely low activation efficiency. The recent invention of ultrahigh-pressure annealing (UHPA) has substantially improved the p-type activation efficiency; however, the UHPA causes an unexpected Mg diffusion. Thus, both annealing processes resulted in a much lower Mg concentration in the GaN matrix than the Mg dose. In this study, the effect of a sequential N I/I for p-type Mg-implanted GaN was investigated by the correlative cathodoluminescence, transfer length method, scanning transmission electron microscopy, and atom probe tomography (APT) analyses. APT results have revealed that the sequential N I/I can successfully maintain the Mg concentration in the GaN matrix in the higher range of 1018 cm−3 or more. Our investigation suggests that sequential N I/I is a promising technique to maintain the Mg concentration higher and improve the p-type activation efficiency. [ABSTRACT FROM AUTHOR]

The manufacture of bipolar junctions is necessary in many 4H-SiC electronic devices, e.g., junction termination extensions and p + in diodes for voltage class > --> 10 kV. However, the presence of electrically active levels in the drift layer that act as minority charge carrier lifetime killers, like the carbon vacancy (V C), undermines device performance. In the present study, we compared p + n diodes whose anodes have been manufactured by three different methods: by epitaxial growth, ion implantation, or plasma immersion ion implantation (PIII). The identification of the electrically active defects in the drift layers of these devices revealed that a substantial concentration of V C is present in the diodes with epitaxial grown or ion implanted anode. On the other hand, no presence of V C could be detected when the anode is formed by PIII and this is attributed to the effects of strain in the anode region. Our investigation shows that PIII can be a useful technique for the manufacture of bipolar devices with a reduced concentration of lifetime killer defects. [ABSTRACT FROM AUTHOR]

The study of light-emitting defects in silicon created by ion implantation has gained renewed interest with the development of quantum optical devices. Improving techniques for creating and optimizing these defects remains a major focus. This work presents a comprehensive analysis of a photoluminescence line at a wavelength of 1240 nm (1 eV) caused by defects arising from the ion irradiation of the SiO2/Si system and subsequent thermal annealing. It is assumed that this emission is due to the formation of defect complexes WM with trigonal symmetry similar to the well-known W-centers. A distinctive feature of these defects is their thermal resistance up to temperatures of 800 °C and less pronounced temperature quenching compared to the W-line. The difference in the properties of these defect centers and W-centers can be explained by their different defect environments, resulting from the larger spatial separation between vacancies and interstitial atoms diffusing from the irradiated layer. This, in turn, is associated with the difference in the distribution of primary radiation defects during irradiation of the SiO2/Si system and silicon not covered with a SiO2 film. The patterns of changes in the WM line depending on various factors, such as the thickness of the SiO2 film, type of conductivity and impurity concentration in the original silicon, irradiation parameters, and annealing regimes, is studied and explained in detail. These findings demonstrate the benefits of this new approach when compared to previous methods. [ABSTRACT FROM AUTHOR]

In this work, nitrogen vacancy (NV) centers of high nitrogen diamond implanted with arsenic ions were investigated by photoluminescence spectroscopy. The transition of the NV center charge state was discussed by the regularly changing laser excitation power and measurement temperature following high-temperature annealing. After high-temperature annealing, the amorphous layer generated by arsenic ion implantation is transformed into a graphitization layer, resulting in a decrease in the NV yield. The electric neutral NV (NV0) center and negatively charged NV (NV−) center are affected by both radiation recombination and Auger recombination with increasing laser power. Accompanied by the increasing measurement temperature, the intensities of NV centers gradually decreased and eventually quenched. In addition, the charge states of NV− and NV0 centers were undergoing a transition. The zero phonon line positions of NV centers were also red shift, it was attributed to the dominant role of electron–phonon interaction in the temperature-dependent displacement of diamond energy gaps. The full width at half maxima of NV center were broadened significantly at higher temperatures. [ABSTRACT FROM AUTHOR]

A significant development toward semiconductor-based electronic devices is based on the electric and magneto-electric control of the transport properties of the charge carriers. This study unprecedentedly investigates the Ti implantation and thereafter the effect of structural defects on the electrical and magneto-electric transport properties of Ti-implanted RF-sputtered ZnO thin films. Theoretical stopping and range of ions in matter simulations along with the experimental structural and elemental studies reveal that Ti ion implantation generates a significant amount of oxygen vacancy (VO) defects apart from Ti-related impurities in post-implantation annealed films. The film implanted with 8 × 1015 ions/cm2 (TZO815) exhibits the lowest resistivity (4.68 × 10−3 Ω cm) and the highest carrier concentration (6.61 × 1020 cm−3) values. Resistivity measurements over a temperature range of 5-300K indicate semiconducting behavior for all the films implanted up to fluences of 5 × 1015 ions/cm2 identified with a grain boundary dominated thermally activated band, nearest neighbor hopping, and Mott and Efros–Shklovskii (ES) variable range hopping conduction mechanisms at various temperature intervals. Notably, the gradual decrease in both Mott and ES hopping ranges following Ti implantation indicates the formation of more localized states. Interestingly, the TZO815 film exhibits metal-semiconductor transition around 220 K, suggesting the formation of a degenerate band within the ZnO conduction band upon Ti implantation. Remarkably, the magnetoresistance results align with a semiempirical formula proposed by Khosla and Fischer, indicating that a negative magneto resistance in the TZO thin films is attributed to the spin-dependent scattering of conduction electrons by the localized magnetic moments induced mainly by the implantation induced VO defects. [ABSTRACT FROM AUTHOR]

In this work, we present a comprehensive re-evaluation of the iron–gallium (FeGa) recombination parameters in silicon using injection-dependent lifetime spectroscopy (IDLS). Ga-doped silicon wafers (of varying resistivities) with precise concentrations of intentional iron contamination in the silicon wafer bulk, through ion implantation and distribution, were used. The presence of interstitial Fei and FeGa, and their lifetime-limiting effects in these silicon wafers, were confirmed through measuring the effective minority carrier lifetime changes during the conditions that are known to cause FeGa dissociation and association. The presence of Fe was also confirmed by deep-level transient spectroscopy. To ensure accurate IDLS analysis of the FeGa defect in silicon, a lifetime linearization scheme was employed to effectively filter out interference by other defects. Error analysis was employed to find the combination of defect parameters that best fit the experimental data and to ascertain the range of uncertainty associated with the IDLS best-fit results. The optimal fitting of the experimental IDLS by Shockley–Read–Hall statistics produced an electron capture cross section σ n = 2.3 × 10 − 14 c m 2 , hole capture cross section σ p = 1.1 × 10 − 14 c m 2 , and a trap energy level E t = E V + 0.2 − 0.01 + 0.02 eV for the FeGa defect in silicon. The extracted defect parameters are also verified by experimentally measuring the crossover point of Fei and FeGa lifetime curves. [ABSTRACT FROM AUTHOR]

Hyperdoped silicon is a promising material for near-infrared light detection, but to date, the device efficiency has been limited. To optimize photodetectors based on this material that operate at room temperature, we present a detailed study on the electrical nature of gold-hyperdoped silicon formed via ion implantation and pulsed-laser melting (PLM). After PLM processing, oxygen-rich and gold-rich surface layers were identified and a wet etch process was developed to remove them. Resistivity and Hall effect measurements were performed at various stages of device processing. The underlying gold-hyperdoped silicon was found to be semi-insulating, regardless of whether the surface gold was removed by etching or not. We propose a Fermi level pinning model to describe the band bending of the transformed surface layer and propose a promising device architecture for efficient Au-hyperdoped Si photodetectors. [ABSTRACT FROM AUTHOR]

Most semiconductors exhibit a saturation of free carriers when heavily doped with extrinsic dopants. This carrier saturation or "doping limit" is known to be related to the formation of native compensating defects, which, in turn, depends on the energy positions of their conduction band minimum and valence band maximum. Here, we carried out a systematic study on the n-type doping limit of GaAs via ion implantation and showed that this doping limitation can be alleviated by the transient process of pulsed laser melting (PLM). For n-type doping, both group VI (S) and amphoteric group IV (Si and Ge) dopants were implanted in GaAs. For comparison, p-type doping was also studied using Zn as the acceptor. Implanted dopants were activated by the PLM method, and the results are compared to rapid thermal annealing (RTA). Our results reveal that for all n-type dopants, while implantation followed by the RTA results in a similar saturation electron concentration of 2–3 × 1018 cm−3, the transient PLM process is capable of trapping high concentration of dopants in the substitutional site, giving rise to a carrier concentration of >1019 cm−3, exceeding the doping limit of GaAs. However, due to scatterings from point defects generated during PLM, the mobility of n-type GaAs after PLM is low (∼80–260 cm2/V s). Subsequent RTA after PLM (PLM + RTA) is able to remove these point defects and recover the mobility to ∼1000–2000 cm2/V s. The carrier concentrations of these PLM + RTA samples are reduced but are still a factor of 3 higher than RTA only GaAs. This can be understood as the dopants are already incorporated in the substitutional site after PLM; they are less likely to be "deactivated" by subsequent RTA. This work is significant to the understanding of doping mechanisms in semiconductors and provides a means for device applications, which require materials with ultra-high doping. [ABSTRACT FROM AUTHOR]

In this work, unintentionally doped GaN thin films were successfully grown on (0001) c -, (11–20) a - and (10–10) m -plane GaN free-standing substrates using metal–organic chemical vapor deposition. Subsequently, Mg was introduced into the GaN thin films through ion implantation (I/I) to prepare Mg-doped GaN (GaN:Mg). Compared with the c -plane substrate, non-polar a - and m -plane substrates were found to effectively enhance the concentration of MgGa acceptors while reducing the concentration of nitrogen vacancy-related clusters in I/I GaN:Mg. The origins of the ultraviolet luminescence peak, green luminescence band and blue luminescence band were analyzed by photoluminescence (PL) spectra. Two acceptor energy levels of Mg in I/I GaN:Mg were calibrated by measuring low-temperature PL spectra in the range of 5 K to 50 K. [ABSTRACT FROM AUTHOR]

The second-order optical nonlinearity (SON) of thermally poled fused silica was shown for the first time to be significantly improved by the implantation of multi-energy boron (B) ions, and the outcomes were compared with those obtained from the implantation of multi-energy argon (Ar) ions. Second-harmonic (SH) signals in both samples grew roughly linearly as the poling temperature rose. Samples with Ar implants showed a greater increase in SH signal with rising poling temperature. A qualitative explanation for the formation of χ (2) in poled samples can be found in a model of charge hopping and migration through defects. The diminished SH signal in the B-implanted sample is probably caused by the negative charge trapping layer, as well as by B 2 α and E ′ center defects. [ABSTRACT FROM AUTHOR]

The nanoscale fabrication of μm-spaced single-photon emitter arrays is crucial for the development of integrated photonic chips. We report on the fabrication and systematic characterization of germanium-vacancy (GeV) color centers arrays in diamond obtained upon ion implantation at the nanoscale. Ge2+ ion implantations at 35 keV and 70 keV energies were carried out using a focused ion beam (FIB) equipped with a liquid metal alloy ion source. The arrays of emitters are subsequently aligned to ø300 nm nanopillar waveguiding structures, fabricated using a combination of electron-beam lithography and plasma etching. The photon collection efficiency and photoluminescence (PL) signal-to-background ratio increased by a factor 8 with respect to the unstructured sample. The photophysical properties of the GeV emitters fabricated by this approach were unaltered with respect to those found in unprocessed diamond. The efficiency of the overall manufacturing process to fabricate individual GeV centers was assessed. Up to 33% of the fabricated nanopillars, depending on ion implantation parameters, were found to contain single emitters. [ABSTRACT FROM AUTHOR]

This review explores the latest advancements in enhancing the biocompatibility and antibacterial properties of implantable structures, with a focus on titanium (Ti) and its alloys. Titanium implants, widely used in dental and orthopedic applications, demonstrate excellent mechanical strength and biocompatibility, yet face challenges such as peri-implantitis, a bacterial infection that can lead to implant failure. To address these issues, both passive and active surface modification strategies have been developed. Passive modifications, such as altering surface texture and chemistry, aim to prevent bacterial adhesion, while active approaches incorporate antimicrobial agents for sustained infection control. Nanotechnology has emerged as a transformative tool, enabling the creation of nanoscale materials and coatings like TiO2 and ZnO that promote osseointegration and inhibit biofilm formation. Techniques such as plasma spraying, ion implantation, and plasma electrolytic oxidation (PEO) show promising results in improving implant integration and durability. Despite significant progress, further research is needed to refine these technologies, optimize surface properties, and address the clinical challenges associated with implant longevity and safety. This review highlights the intersection of surface engineering, nanotechnology, and biomedical innovation, paving the way for the next generation of implantable devices. [ABSTRACT FROM AUTHOR]

High diffraction efficiency optical transmission gratings with quasi-sinusoidal and saw-tooth surface relief profiles were fabricated in Bi12GeO20, Er: LiNbO3 and Er: Fe: LiNbO3 crystals by ion beam implantation. The gratings were directly written by nitrogen ion microbeams at energies of 5 MeV and 10.5 MeV. The finest grating constant was 4 μm. Grating constants for the majority of the gratings were 16 μm. The highest amplitudes of the gratings reached 1600 nm. The highest first-order diffraction efficiency obtained in a sinusoidal grating was 25%, close to the theoretical maximum of 33%. The highest first-order diffraction efficiency of a blazed grating was also 25%, without Littrow optimization. Such gratings can be incorporated into integrated optical biosensors. [ABSTRACT FROM AUTHOR]