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Photonic integrated circuits (PICs) suffer from birefringence due to high-index contrast. Polarisation handling devices improve the performance of the PICs by reducing the polarisation-dependent dispersion and loss. Furthermore, there is a growing interest in building polarisation division multiplexed transceivers using PICs, which require polarisation management. The authors provide an overview of the recent work on developing polarisation handling devices such as polarisation beam splitters and polarisers in indium phosphide and silicon-on-insulator platforms for optical communications and sensing applications. These devices expand the PICs library of polarisation handling devices and can be used to design more complex circuits with advanced or new functionalities.

Background The blood-brain barrier (BBB) hardly allows all substances to pass. Except for oxygen, carbon dioxide, and blood sugar, most dyes and proteins are generally unable to pass due to their m...

The development of flexible displays for wearable electronics applications has created demand for high-performance quantum dot (QD) light-emitting diodes (QLEDs) based on QD core@shell structures. Emerging indium phosphide (InP)-based core@shell QDs show promise as lighting material in the field of optoelectronics because they are environmentally friendly material, can be produced in a cost-effective manner, and are capable of tunable emission. While efforts have been made to enhance the performance of InP-based QLED, the stabilities of InP@ZnSeS QDs film and InP@ZnSeS-based QLED in water/air are not yet fully understood, limiting their practical applications. Herein, a highly durable, flexible InP@ZnSeS QLED encapsulated in an ultrathin film of CYTOP, a solution-based amorphous fluoropolymer, is demonstrated. The CYTOP-encapsulated green flexible QLED shows an external quantum efficiency (EQE) of 0.904% and a high luminescence of 1593 cd/m2 as well as outstanding waterproof performance. The flexible device emits strong luminescence after being immersed in water for ~20 minutes. Even when subjected to continuous tensile stress with a 5 mm bending radius, the high luminescence is preserved. This waterproof architecture can be a promising strategy for wearable electronics applications.

The authors present a manufacturing cost analysis for producing thin-film indium phosphide modules by combining a novel thin-film vapor–liquid–solid (TF-VLS) growth process with a standard monolithic module platform. The example cell structure is ITO/n-TiO2/p-InP/Mo. For a benchmark scenario of 12% efficient modules, the module cost is estimated to be $0.66/W(DC) and the module cost is calculated to be around $0.36/W(DC) at a long-term potential efficiency of 24%. The manufacturing cost for the TF-VLS growth portion is estimated to be ~$23/m 2 ,as ignificant reduction compared with traditional metalorganic chemical vapor deposition. The analysis here suggests the TF-VLS growth mode could enable lower-cost, high-efficiency III-V photovoltaics compared with manufacturing methods used today and open up possibilities for other optoelectronic applications as well. Copyright © 2016 John Wiley &S ons, Ltd.

Control of quantum dot (QD) precursor chemistry has been expected to help improve the size control and uniformity of III-V QDs such as indium phosphide and indium arsenide. Indeed, experimental results for other QD systems are consistent with the theoretical prediction that the rate of precursor conversion is an important factor controlling QD size and size distribution. We synthesized and characterized the reactivity of a variety of group-V precursors in order to determine if precursor chemistry could be used to improve the quality of III-V QDs. Despite slowing down precursor conversion rate by multiple orders of magnitude, the less reactive precursors do not yield the expected increase in size and improvement in size distribution. This result disproves the widely accepted explanation for the shortcoming of current III-V QD syntheses and points to the need for a new generalizable theoretical picture for the mechanism of QD formation and growth.

We report efficiency enhancement of indium phosphide (InP) quantum dot-based light-emitting diodes (QD-LEDs) by using an polyethylenimine (PEI) surface modifier. By adapting a solution processed PEI layer on top of a aluminum doped zinc oxide (Al:ZnO) nanoparticle (NP) film, the leakage current of the inverted device was substantially suppressed. In addition, the electron injection into the conduction band edge (CBE) of InP/ZnSe/ZnS QDs was also facilitated by the low work function (WF) of the Al:ZnO film which was realized by the strong interfacial dipoles of the thin film of PEI. As a result, the charge balance in the inverted devices was controlled by the change of surface roughness, the WF and the thickness of neighboring layers via spin-coating the PEI dissolved in alcohol mixture on the Al:ZnO layer such that the current efficiency was dramatically increased from 0.07 cd/A to 3.17 cd/A. The performance of our device is not comparable to Cd-based devices; however, it shows the great potential for using an interfacial dipole layer to develop highly efficient InP-based inverted QD-LEDs.

Semiconductor quantum dots (QDs) promise facile color tuning and high color saturation in quantum-dot light-emitting devices (QD-LEDs) by controlling nanoparticle size and size distribution. Here, we demonstrate how this promise can be practically realized for the cadmium-free InP/ZnSe/ZnS multishell quantum dots. We developed a set of synthesis conditions and core/shell compositions that result in QDs with green, yellow, and red emission color. The QD-LEDs employing these QDs show efficient electroluminescence (EL) with luminance up to 1800 cd/m2 and efficiency up to 5.1 cd/A. The color coordinates calculated from the EL spectra clearly demonstrate the outstanding color saturation as an outcome of the narrow particle size distribution. These results prove that the performance gap between cadmium-free and cadmium-based QDs in QD-LEDs is shrinking rapidly.

Wide color gamut displays on the market were studied. TVs displaying over 90% NTSC gamut area and monitors displaying over 100% Adobe coverage were selected. CdSe QD based solutions achieve the highest color and energy efficiency, which is linked to fundamental attributes of QDs: narrow emission, efficiency, and operational stability.

The density matrix of a spin S = 9/2 excited by a radiofrequency pulse is calculated. The interaction involved during the excitation of the spin system is first-order quadrupolar. Consequently, the results are valid for any ratio of the quadrupolar coupling ωQ to the pulse amplitude ω1. The behavior of the central transition intensities versus the pulse length is discussed. The 115In and 113In nuclei in a powdered sample of indium phosphide (InP) are used to illustrate the results. It is found that the ratio of the quadrupolar coupling constants determined in this work is in excellent agreement with the ratio of the quadrupole moments of the two nuclei. Copyright © 2015 John Wiley & Sons, Ltd.

This paper describes our finding that optical properties of semiconductor nanowires were modified by depositing a thin layer of metal oxide. Indium phosphide nanowires were grown by metal organic chemical vapor deposition on silicon substrates with gold catalyst resulting in three-dimensional nanowire networks, and optical properties were obtained from the collective nanowire networks. The networks were coated with an aluminum oxide thin film deposited by plasma-enhanced atomic layer deposition. We studied the dependence of the peak wavelength of photoluminescence spectra on the thickness of the oxide coatings. A continuous blue shift in photoluminescence spectra was observed when the thickness of the oxide coating was increased. The observed blue shift is attributed to the Burstein–Moss effect due to increased carrier concentration in the nanowire cores caused by repulsion from intrinsic negative fixed charges located at the inner oxide surface. Samples were further characterized by scanning electron microscopy, Raman spectroscopy, transmission electron microscopy, and selective area diffractometry to better understand the physical mechanisms for the blue shift. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

InP quantum dots have emerged as an exciting class of phosphors for displays and energy-efficient solid state lighting. Unfortunately, the synthesis of these materials has lagged behind that of related II-VI and IV-VI materials. It is becoming increasingly apparent that this may be due, in many cases, to the inability to control quantum dot nucleation and crystallization using precursor conversion kinetics. In this perspective, recent work on understanding the nucleation and growth of InP from the perspective of nonclassical nucleation models is discussed. In particular, the recent discovery that kinetically persistent magic-size nanoclusters build up during the high temperature synthesis of this material will be highlighted. Isolation and complete structural characterization of one such InP nanocluster has offered unprecedented insight into the structure and surface chemistry of InP and its deviation from how we think about quantum dot structure and composition based on models built for II-VI materials. ...

The use of nanoimprint lithography, a low cost and time saving alternative to E-beam lithography, for growing heteroepitaxial indium phosphide layer on silicon is demonstrated. Two types of pattern ...

The influence of hot phonon effect and intervalley scattering on the hot carrier cooling rate was investigated using femtosecond time-resolved photoluminescence spectroscopy in bulk GaAs and InP, two electronically similar but vibrationally distinct semiconductors. In both materials, a broad photoluminescence signal that extends from the band gap energy to values larger than the pump pulse energy was observed during the first few picoseconds after photoexcitation, for different excitation energies (1.7, 1.88, and 2.4 eV) at high carrier densities (>1019 cm−3). Different hot carrier relaxation times were observed in GaAs and InP for different excitation energies, demonstrating the influence of intervalley scattering phenomena in GaAs. When electrons were not energetic enough to access satellite valleys, longer decay transients were observed for InP compared with GaAs. This provides experimental evidence of the hot phonon effect in InP. Temperature transients were calculated by analyzing the topography of the two-dimensional spectra. Copyright © 2011 John Wiley & Sons, Ltd.

We are proposing a novel structure containing GaInNAs n–i–p–i layers with a band gap of 1 eV connected in series to a GaInP/GaAs tandem structure. The device performance is modelled using the drift diffusion conductivity model where the number and thickness of the layers are taken as adjustable parameters to achieve the optimum design. We obtain the value of short-circuit current to keep the n–i–p–i cell current matched to the other junctions in the tandem structure.

The contactless electrical characterization techniques MDP and MD-PICTS will be presented in this paper. Both methods are predestined for defect investigation in a variety of semiconductors. Due to a so far not reached sensitivity, major advantages of MDP are its high spatial resolution and its measurement speed, which allows for two dimensional inline measurements at production speed. Furthermore a versatile numerical tool for simulations of electrical properties of a semiconductor as a function of defect parameters was developed. MD-PICTS is a contactless temperature dependent measurement which allows the determination of activation energies of trap levels in the material. To demonstrate the abilities of both methods, measurements conducted at different semiconductor materials, e.g. silicon, silicon carbide, gallium arsenide and indium phosphide, will be presented exemplarily.

Four tunnel junction (TJ) designs for multijunction (MJ) solar cells under high concentration are studied to determine the peak tunnelling current and resistance change as a function of the doping concentration. These four TJ designs are: AlGaAs/AlGaAs, GaAs/GaAs, AlGaAs/InGaP and AlGaAs/GaAs. Time-dependent and time-average methods are used to experimentally characterize the entire current–voltage profile of TJ mesa structures. Experimentally calibrated numerical models are used to determine the minimum doping concentration required for each TJ design to operate within a MJ solar cell up to 2000-suns concentration. The AlGaAs/GaAs TJ design is found to require the least doping concentration to reach a resistance of

The complex linear electro-optic coefficient d 41 was determined for the first time above the fundamental band gap of GaAs and InP by measuring the doping induced band bending of several oxidized samples in reflectance anisotropy spectroscopy. From the real and imaginary part of the change of the spectra for different carrier concentrations the spectral change of d 41 was calculated. This is the first determination of the imaginary part Im (d 41 ).

Focused ion beam implantation of 30 keV Ga + ions in single-crystalline InP was investigated by SIMS, using Cs + primary ions for sputtering. Nine different implantation fluences ranging from 1 × 10 13 to 1 × 10 17 Ga + ions/cm 2 were used, with implanted areas of 50 x 50 μm 2 . The Ga concentration distributions of these implants were determined by SIMS depth profiling. Such 30 keV Ga implantations were also simulated by a dynamic Monte Carlo simulation code that takes into account the gradual change of the near-surface composition due to the Ga incorporation. In both approaches, an essentially linear increase of the Ga content with fluence is found up to ~1 x 10 16 cm -2 ; for higher fluences, the Ga peak concentration approaches a saturation level which is reached at about (0.5-1) × 10 17 cm -2 and amounts to ~10%. The measured and simulated concentrations of the Ga distributions are in good agreement. The most probable range of the Ga + ions in InP obtained from the SIMS experiments is ~23 nm and matches closely with the value from the simulations.

A theoretical conversion efficiency of 36.4% at 1000 suns concentration has been determined by means of realistic models and an improved optimization routine. The starting point device was the recent world-record monolithic GaInP/GaAs dual-junction solar cell that was grown lattice matched on a GaAs substrate by MOVPE, which has an efficiency of 32.6% at 1000 suns. Using previously calibrated models developed at our institution, IES-UPM, together with Silvaco ATLAS TCAD software, we reproduced the characteristics of the world-record solar cell, and then determined a cell configuration that would yield greater efficiency by using an optimization routine to hone the doping concentration and the thickness of each layer.

The sequence of high pressure phases in InP and InAs crystals was studied by density functional calculations. The transition from ambient pressure zinc-blende to rocksalt (NaCl) phase is of the first order and transitions pressures for crystals are in agreement with experiments. The high pressure phase transition from cubic NaCl phase to orthorhombic Cmcm phase in InP and InAs was studied by monitoring the pressure dependence of transversal acoustic (TA) phonon frequencies. Lattice dynamics calculations reveal that the rocksalt structure is unstable with respect to TA mode at a single point on the Brillouin zone boundary. The observed pressures of the phase transitions in structural measurements were reproduced more accurately then in previous calculations.

InP is grown on Si by nano-epitaxial lateral overgrowth (NELOG or nano-ELOG) on patterns consisting of net-type openings under different growth conditions. Surface morphology is characterized with ...

The electrical, structural and surface morphological properties of Mo/n-InP Schottky diodes have been investigated as a function of annealing temperature using current–voltage (I–V), capacitance–voltage (C–V), Secondary Ion Mass Spectroscopy (SIMS), X-ray diffraction (XRD) and atomic force microscopy (AFM) measurements. The obtained Schottky barrier heights from I–V and C–V measurements for as-deposited Mo/n-InP are 0.45 eV and 0.61 eV respectively. Upon annealing at 300 °C in nitrogen atmosphere for 1 min, the barrier height values increased to 0.47 eV (I–V) and 0.68 eV (C–V). When the samples are annealed at temperatures 400 and 500 °C, the barrier height values decrease to 0.46 eV (I–V), 0.44 eV (I–V) and 0.65 eV (C–V), 0.64 eV (C–V). The SIMS and XRD results showed the formation of phosphide phases at the Mo/n-InP interface, which may be the reason for the decrease in the barrier height for samples annealed at 500 °C. The AFM measurements showed that the surface morphology of Mo contacts on n-InP is smooth with a root mean square value of 12.7 nm even after annealing at 500 °C. Copyright © 2009 John Wiley & Sons, Ltd.

True colors: High-quality InP and InP/ZnS quantum dots (QDs) are obtained by means of a simple one-pot method in the presence of polyethylene glycol (PEG). Rapid and size-controlled reactions lead to highly crystalline and nearly monodisperse QDs at relatively low temperatures. The particles emit from cyan blue to far-red, and are successfully used in cellular imaging (see figure).

The effects of rapid thermal annealing on the electrical and structural properties of Ru/n-InP Schottky diode have been investigated by current–voltage (I–V), capacitance–voltage (C–V), X-ray diffraction (XRD) and secondary ion-mass spectroscopy (SIMS) techniques. Results showed that the Schottky barrier height of the as-deposited Ru/n-InP has been found to be 0.53 eV (I–V) and 0.69 eV (C–V). The Schottky barrier height increased to 0.54 eV (I–V) 0.73 eV (C–V), 0.56 eV (I–V) and 0.78 eV (C–V) after annealing at 300 and 400 °C for 1 min in nitrogen ambient. Further increase in the annealing temperature up to 500 °C resulted in the increase of barrier height to 0.57 eV (I–V) and 0.80 eV (C–V). However, after annealing at temperature 600 °C, the barrier height decreases to 0.51 eV (I–V) and 0.67 eV (C–V). Based on the results of XRD and SIMS studies, the formation of indium phases at Ru/n-InP interface could be the reason for the increase of barrier height upon annealing at 500 °C. The atomic force microscopy results showed that the surface morphology of the contact annealed at 600 °C is fairly smooth with a root mean square roughness of 1.8 nm.

Various crystallographic planes are exposed when growing along mesa sidewalls during metalorganic vapor phase epitaxy. Dopant incorporation and activation on these higher index surfaces can be quite different from that observed on (001) surfaces. Incorporation and activation of Si and Fe in MOVPE grown InP on (001), (110), and (311)A and B surfaces are reported. The Si donor concentration is higher on the P-terminated B surface than the A surface while the opposite behavior is observed for Fe incorporation. In the fabrication of optoelectronic devices, it must be remembered that it is the carrier concentration, that is, activated atomic species, that is relevant for device performance and not the incorporation of atomic species alone. Activation of Si is >1 on all surfaces; however, Fe is shown to be an effective compensating species only on the (001) and (311)A crystallographic surfaces. Data for the presence of oscillations in the iron concentration on (001) surfaces are also reported. The active Fe concentration is shown to be related to the Fe atomic concentration relative to the donor density on the different crystallographic surfaces, suggesting that Fermi level position sets a limit to the fraction of Fe centers which are electrically active as a deep trap. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The effects of rapid thermal annealing on the electrical and structural properties of Pd/Au Schottky contacts to n-type InP(111) have been investigated by current–voltage (I –V), capacitance–voltage (C –V) and X-ray diffraction (XRD) measurements. The barrier height of the as-deposited Pd/Au Schottky contact was found to be 0.46 eV (I –V) and 0.70 eV (C –V) respectively. It is observed that the Schottky barrier height increases with annealing temperature and found maximum values of 0.51 eV (I –V) and 0.92 eV (C –V) annealed at 400 °C for 1 min in the nitrogen atmosphere. However, after annealing the sample at 500 °C resulted in the decrease of barrier height and values are 0.40 eV (I –V) and 0.60 eV (C –V). The AFM results showed that the surface morphology of the contact annealed at 500 °C is fairly smooth with a RMS roughness 1.9 nm. Based on the XRD results, the formation of indium phases at the Pd/Au/n-InP interface could be the reason for the increase in the Schottky barrier height at 400 °C. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The polypyrrole/p-InP structure has been fabricated by the electrochemical polymerization of the organic polypyrrole onto the p-InP substrate. The current–voltage (I–V), capacitance–voltage (C–V), and capacitance–frequency (C–f) characteristics of the PPy/p-InP structure have been determined at room temperature. The structure showed nonideal I–V behavior with the ideality factor and the barrier height 1.48 and 0.69 eV respectively. C–f measurements of the structure have been carried out using the Schottky capacitance spectroscopy technique and it has been seen that there is a good agreement between the experimental and theoretical values. Also, it has been seen that capacitance almost show a plateau up to a certain value of frequency, after which, the capacitance decreases. The higher values of capacitance at low frequencies were attributed to the excess capacitance resulting from the interface states in equilibrium with the p-InP that can follow the a.c. signal. The interface state density Nss and relaxation time τ of the structure were determined from C–f characteristics. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1572–1579, 2006

The evolution of the base current of GaInP/GaAs Heterojunction Bipolar Transistors (HBTs) is studied as a function of the stressing current during the burn-in. It is found that the base current decreases in an exponential way with the involved time constants depending themselves on the stressing current in a way proportional to I -2 . Such behaviour is explained considering two independent recombination centres that are deactivated during the stressing by the capture of two electrons. These two recombination centres might be H + and the quasi complex Si + -H + which capture two electrons each becoming H - and SiH.

This paper describes a double-sideband, upconverting transmitter module with a potential application to future-generation point-to-point telecommunications in the 176–190-GHz band. The multichip module incorporates indium phosphide (InP) and gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs). It is believed that this is the first time an all-MMIC transmitter module has been reported in this frequency band. The small-signal up-conversion gain falls approximately monotonically from 0 dB for output at 176 GHz, to −15 dB for output at 190 GHz. The input frequency range covers 0.5 to 9 GHz and the local oscillator can be tuned from 45 to 47 GHz. Gain compression of 1-dB occurs at an output power of −12 dBm at 176 GHz, decreasing to −20 dBm at 190 GHz. Output 3rd-order intercept point is +1 dBm at 176 GHz, decreasing to −12 dBm at 190 GHz. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 338–341, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21343

We investigated the optoelectronic characteristics of QD-LEDs by tuning ZnS shell thickness of InP/ZnSe/ZnS multishell QDs. Current efficiency of our QD-LEDs fabricated using thicker ZnS shell of QDs was enhanced up to 4.65 cd/A. It is one of the promising results reported so far for Cd-free QD-LEDs.

The growth of high-quality stoichiometric indium phosphide by atmospheric pressure metal-organic chemical vapor deposition within thin-film artificial opals has been optimized. The optical properties of these systems have been studied as a function of the filling fraction. A consistent behavior has been found which substantially differs from that of other common infilled opals. The evolution of the InP morphology seems to be strongly correlated with this anomalous photonic response. At the first infiltration stages, the growth leads to the formation of nanocrystallites that eventually, as the infiltration increases, coalesce in single-crystalline grains of increasing size. The possibility to oxidize the material adds to its potential as a useful optical material. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

This work investigated the effects of hydrostatic pressure on the properties and bistability of the scientifically challenging and technologically important deep MFe center in iron (Fe)-doped, n-type indium phosphide (InP). When occupied by electrons, the center can be reversibly placed in either of two configurations, termed A and B, by the proper choice of electric biasing conditions and temperature. Pressure has a very large influence on the balance between these two configurations, favoring A over B. Above 8 kbar essentially only the A configuration is observed. This result, along with detailed studies of the effects of pressure on the energetics of the two configurations and on the kinetics of the B {yields} A transformation, provide important new insights about the nature of the two configurations and their associated deep levels.

This paper describes a low-noise, high-gain, single-sideband, downconverting receiver module developed for point-to-point telecommunications in the 82–104-GHz range. Two indium phosphide (InP) and two gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs) are used in the multi-chip module. For RF frequencies in the 82–104-GHz range and within a 1–3-GHz IF band, the receiver exhibits a typical single-sideband down-conversion gain between 15 and 20 dB and a typical noise figure of between 4 and 5 dB. In the same frequency range, the suppression of the unwanted sideband is typically −15 dB or more. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 92–95, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20218