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The nanometer-range Indium Arsenide Composite Channel (IACC) High Electron Mobility Transistors (HEMTs) are fabricated on 100 mm Indium Phosphide (InP) substrates. This technology offers the best performance for low-noise and high-frequency, space and military applications. Typical failure mechanisms are observed in III-V HEMT technologies, including gate sinking and oxidation. Experiments were conducted to determine if these failure mechanisms degrade the IACC HEMTs after updating the new HEMT. The experiments conducted were life tests completed at accelerated temperatures and biases with a thin Si3N4 passivation layer; the devices’ electrical characteristics were measured at each stress interval. The failure mechanisms examined within this dissertation include: gate sinking, which is the interdiffusion of the metal gate into the semiconductor. Therefore, a temperature stress was done to initiate the mechanism; oxidation is the migration of oxygen atoms into materials are induced by a high electric field and high temperature. The Si3N4 passivation thickness was then increased to determine if the degradation of the electrical parameters could be decreased. Four HEMTs were placed on a Low-Noise Amplifier (LNA) circuit, therefore, an additional LNA assessment was completed to determine which device degraded and where the defect might be located; the Low-Noise Amplifier (LNA) Circuit assessment determines the limiting HEMT in the LNA circuit. Since many of the known III-V semiconductor failure mechanisms physically degrade or damage HEMTs, cross-sections are important to prepare to detect these mechanisms. Advanced microscopy techniques, with sub-nanometer resolutions, examined physical characteristics of the HEMT at the atomic scale. Each device was cross-sectioned with a Focused Ion Beam/Scanning Electron Microscope (FIB/SEM) and polished with a Nanomill to about 100 nm thickness at the gate fingers to look for the failure mechanisms. The Scanning Transmission Electron Microscope (STEM) along with Energy Dispersive Spectroscopy (EDS) was then used to see the oxygen in the titanium gate layer and no gate sinking. TCAD modeling simulations were used to verify these results and show that the Schottky barrier height changes and the oxygen diffuses faster through the titanium gate layer due to the electric-field increase.

III–V compound nanowires have electrical and optical properties suitable for a wide range of applications, including photovoltaics and photodetectors. Furthermore, their elastic nature allows the use of strain engineering to enhance their performance. Here we have investigated the effect of mechanical strain on the photocurrent and the electrical properties of single GaAs nanowires with radial p-i-n junctions, using a nanoprobing setup. A uniaxial tensile strain of 3% resulted in an increase in photocurrent by more than a factor of 4 during NIR illumination. This effect is attributed to a decrease of 0.2 eV in nanowire bandgap energy, revealed by analysis of the current–voltage characteristics as a function of strain. This analysis also shows how other properties are affected by the strain, including the nanowire resistance. Furthermore, electron-beam-induced current maps show that the charge collection efficiency within the nanowire is unaffected by strain measured up to 0.9%.

We report uniform Type-II GaInAsSb/InP UTC-PDs, and compare their performance to devices fabricated with GaAsSb uniform and graded (composition and doping) absorbers of the same thickness. The quaternary UTC-PDs show a transit limited bandwidth of 274 GHz in contrast to 107 and 185 GHz for uniform and graded GaAsSb absorber UTC-PDs. Because the uniform quaternary and ternary UTC-PDs only differ in their absorber material, the findings conclusively demonstrate enhanced transport in GaInAsSb. Performance comparison to GaInAs-based devices from the literature suggest that GaInAsSb is a superior absorber material for λ = 1.55 μm high-speed photodetectors. Additionally, the external responsivity of the GaInAsSb UTC-PDs (0.094 A/W) is ~34% higher than the GaAsSb PDs (0.070 A/W). This is the first demonstration of a quaternary GaInAsSb absorber in UTC-PDs., Journal of Lightwave Technology, 39 (7), ISSN:0733-8724, ISSN:1558-2213

We present broadband MMI couplers, developed for a novel integration platform on InP with active/passive integration capabilities for the 1300nm wavelength range. Low loss (

Conventional pseudomorphic high electron mobility transistor (pHEMTs) with lattice-matched InGaAs/InAlAs/InP structures exhibit high mobility and saturation velocity and are hence attractive for the fabrication of three-terminal low-noise and high-frequency devices, which operate at room temperature. The major drawbacks of conventional pHEMT devices are the very low breakdown voltage (xGa(1−x)As (x = 0.53 or 0.7) channel material plus the contribution of other parts of the epitaxial structure. The capability to achieve higher frequency operation is also hindered in conventional InGaAs/InAlAs/InP pHEMTs, due to the standard 1 μm flat gate length technology used. A key challenge in solving these issues is the optimization of the InGaAs/InAlAs epilayer structure through band gap engineering. A related challenge is the fabrication of submicron gate length devices using I-line optical lithography, which is more cost-effective, compared to the use of e-Beam lithography. The main goal for this research involves a radical departure from the conventional InGaAs/InAlAs/InP pHEMT structures by designing new and advanced epilayer structures, which significantly improves the performance of conventional low-noise pHEMT devices and at the same time preserves the radio frequency (RF) characteristics. The optimization of the submicron T-gate length process is performed by introducing a new technique to further scale down the bottom gate opening. The outstanding achievements of the new design approach are 90% less gate current leakage and 70% improvement in breakdown voltage, compared with the conventional design. Furthermore, the submicron T-gate length process also shows an increase of about 58% and 33% in fT and fmax, respectively, compared to the conventional 1 μm gate length process. Consequently, the remarkable performance of this new design structure, together with a submicron gate length facilitatesthe implementation of excellent low-noise applications.

Direct bonding is a materials integration process in which wafer substrates are directly bonded without any intermediate layers. This technique has been used to fabricate direct bonded n-GaAs//n-GaAs, n-GaAs//n-InP, and n-InP//n-InP structures comprised of combinations of on-axis substrates and substrates with (001) faces misoriented 4° toward in order to study the effect of relative surface misorientation on the electrical properties of the bonded interface. Simulation and measurement of interface electrical conductivity were used to identify properties including height and shape of the potential barrier. Across all substrate combinations, as the relative surface misorientation was increased, the interface resistance and height of the interfacial potential barrier also increased. Current density – voltage measurements of GaAs//InP bonded structures revealed no band structure asymmetry at low ( ± 50 mV) bias. Transmission electron microscopy was used to observe the morphology of the interface between InP//InP and GaAs//InP structures. Consistent with previous reports, results of electrical measurements indicate that the potential barrier height at interfaces containing at least one side InP are less sensitive to increased interface resistance with increasing misorientation. Low temperature (≤ 600 °C) and kPa applied pressure to initiate bonding between (NH4S)2 pretreated GaAs and InP wafers was used to fabricate direct bonded structures. Wafers were bonded face-to-face on-axis, with relative misorientation of 4° or 8°, or a by bonding a combination of 4° miscut substrates bonded such that relative misorientation was zero. The samples were annealed at 400 °C for 2 hours to strengthen the bond, and then subjected to rapid thermal processing at 600 °C for 2 minutes to improve the electrical conductivity. When compared to on-axis structures, the interface resistance at room temperature for 4° misoriented bonded pairs increased from 0.011 Ω∙cm2 to 2.8 Ω∙cm2 for GaAs//GaAs structures, from 0.00824 Ω∙cm2 to 0.0161 Ω∙cm2 for GaAs//InP structures and only from 0.0063 Ω∙cm2 to 0.0089 Ω∙cm2 for InP//InP structures. The electronic behavior at the interface was modeled using the Seager-Pike theoretical model for electron tunneling between adjacent semiconductor bicrystals. In accordance with this model the zero-bias conductance was used to estimate the conduction barrier height at the bonded interface. The zero-bias conductance taken at temperatures from 90 to 340 K reveals an increase in potential barrier height across all wafer combinations as the degree of surface misorientation is increased, from 0.26 eV to 0.305 eV for InP//InP structures, from 0.32 eV to 0.39 eV for GaAs//InP structures, and from 0.54 eV to 1.0 eV for GaAs//GaAs structures. For all material combinations studied, structures with zero relative misorientation displayed equivalent electrical performance to nominal on-axis substrates, demonstrating that relative surface misorientation rather than substrate miscut is responsible for changes in electrical resistivity. The large increase in potential barrier height for GaAs//GaAs structures indicates that the degree of relative misorientation between GaAs//GaAs wafer bonded pairs has a significant impact on interface electrical properties, and is consistent with previous GaAs//GaAs studies. However for GaAs//InP wafer bonded pairs, the relative misorientation across the bonded interface plays a less significant role, and the impact of relative misorientation is least significant for InP/.InP bonded structures. This is illustrated by the increase in potential barrier of 0.04 eV for InP//InP structures, 0.06 eV for GaAs//InP structures, and 0.47 eV for GaAs//GaAs structures as relative misorientation is increased from 0° to 8°. High resolution transmission electron microscopy and high-angle annular dark field are used to confirm the misorientation of GaAs//InP and InP//InP bonded samples and determine the interface morphology. No interfacial layer is present in InP//InP structures before or after rapid thermal processing. It is observed that regions adjacent to the interface undergo a process of atomic redistribution and recrystallize into the same lattice arrangement as the bulk semiconductor. GaAs//InP interfaces are observed to contain regions direct substrate contact with oxide inclusions in between after rapid thermal processing, consistent with previous work on GaAs//GaAs interfaces. It is concluded that for III-V direct wafer bonded heterostructures, interface conductivity is a function of both the relative misorientation between the (001) surfaces and the material pair. The significance of this study is that the additional variable of lattice mismatch does not degrade electrical conductivity through GaAs//InP interfaces. This is significant for applications where heterostructure interface conduction must be controlled, such as the direct bonding of III-V wafers for photovoltaic applications.

Numerical simulation of the electric field distribution and photocurrent response of a planar InP/InGaAs avalanche photodiode is presented as a function of varying multiplication width. The Zn dopant diffusion front is obtained by numerically simulating the diffusion process. The simulation results indicate that while a local peak value of the electric field is observed near the device edge, it is not associated with a significant increase in the photocurrent response., 2021 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD), September 13-17, 2021, Turin, Italy

With classical molecular dynamics simulations, we demonstrated that doping of the InP crystal with Zn and S atoms reduces the pressure of the B3→B1 phase transformation as well as inhibits the development of a dislocation structure. On this basis, we propose a method for determining the phenomenon that initiates nanoscale plasticity in semiconductors. When applied to the outcomes of nanoindentation experiments, it predicts the dislocation origin of the elastic-plastic transition in InP crystal and the phase transformation origin of GaAs incipient plasticity.

High-performance optical power converters (OPCs) enable isolated electrical power and power beaming applications at new wavelengths and higher output powers. Broadcom’s vertical epitaxial heterostructure architecture (VEHSA) multi-junction OPCs permit optical-to-electrical conversion at high efficiency and at manageable external loads. This study provides details of how the power outputs have been extended from 20 W. The work also provides details of how the spectral range options have been extended from 800–830 nm to other key laser diode wavelengths such as 960–990 nm and 1500–1600 nm.

We report optical phonon vibration modes in ensembles of self-catalyzed InP/InAs/InP multi core-shell one-dimensional nanostructures (nanopillars and nanocones) grown on InP(111)B substrates using liquid indium droplets as a catalyst via metal-organic chemical vapor deposition. We characterized the Raman vibration modes of InAs E1(TO), InAs A1(TO), InAs E1(LO), InP E1(TO), InP A1(LO), and InP E1(LO) from the ensemble of as-grown nanostructures. We also identified second-order Raman vibration modes, associated with InP E1(2TO), E1(LO+TO), and E1(2LO), in the InP/InAs/InP core-shell nanopillars and nanocones. Raman spectra of InP/InAs/InP nanopillars showed redshift and broadening of LO modes at low-frequency branches of InAs and InP. Due to the polar nature in groups III–V nanowires, we observed strong frequency splitting between InAs E1(TO) and InAs A1(LO) in InP/InAs/InP nanocones. The Raman resonance intensities of InP and InAs LO modes are found to be changed linearly with an excitation power. By tilting the substrate relative to the incoming laser beam, we observed strong suppression of low-frequency branch of InP and InAs LO phonon vibrations from InP/InAs/InP nanocones. The integrated intensity ratio of InP E1(TO)/E1(LO) for both nanostructures is almost constant at 0-degree tilt, but the ratio of the nanocones is dramatically increased at 30-degree tilt. Our results suggest that Raman spectroscopy characterization with a simple substrate tilting method can provide new insights into non-destructive characterization of the shape, structure, and composition of the as-grown nanostructures for the wafer-scale growth and integration processing of groups III–V semiconducting hetero-nanostructures into nanoelectronics and photonics applications.

Nanostructures composed of dielectric, metallic or metalo-dielectric structures are receiving significant attention due to their unique capabilities to manipulate light for a wide range of functions such as spectral colors, anti-reflection and enhanced light-matter interaction. The optical properties of such nanostructures are determined not only by the shape and dimensions of the structures but also by their spatial arrangement. Here, we demonstrate the generation of vivid colors from nanostructures composed of spatially disordered metalo-dielectric (In/InP) nanopillar arrays. The nanopillars are formed by a single-step, ion-sputtering-assisted, self-assembly process that is inherently scalable and avoids complex patterning and deposition procedures. The In/InP nanopillar dimensions can be changed in a controlled manner by varying the sputter duration, resulting in reflective colors from pale blue to dark red. The fast Fourier transform (FFT) analysis of the distribution of the formed nanopillars shows that they are spatially disordered. The electromagnetic simulations combined with the optical measurements show that the reflectance spectra are strongly influenced by the pillar dimensions. While the specular and diffuse reflectance components are appreciable in all the nanopillar samples, the specular part dominates for the shorter nanopillars, thereby leading to a glossy effect. The simulation results show that the characteristic features in the observed specular and diffused reflectance spectra are determined by the modal and light-scattering properties of single pillars. While the work focuses on the In/InP system, the findings are relevant in a wider context of structural color generation from other types of metalo-dielectric nanopillar arrays.

International audience; Chemical characterization at buried interfaces is a real challenge, as the physico-chemical processes operating at the interface govern the properties of many systems and devices. We have developed a methodology based on the combined use of pulsed RF GD-OES (pulsed Radio Frequency Glow Discharge Optical Emission Spectrometry) and XPS (X-ray Photoelectron Spectroscopy) to facilitate the access to deeply buried locations (taking advantage of the high profiling rate of the GD-OES) and perform an accurate chemical diagnosis using XPS directly inside the GD crater. The reliability of the chemical information is, however, influenced by a perturbed layer present at the surface of the crater, hindering traditional XPS examination due to a relatively short sampling depth. Sampling below the perturbed layer may, however, can be achieved using a higher energy excitation source with an increased sampling depth, and is enabled here by a new laboratory-based HAXPES (Hard X-ray PhotoElectron Spectroscopy) (Ga-Kα, 9.25 keV). This new approach combining HAXPES with pulsed RF GD-OES requires benchmarking and is here demonstrated and evaluated on InP. The perturbed depth is estimated and the consistency of the chemical information measured is demonstrated, offering a new route for advanced chemical depth profiling through coatings and heterostructures.

InP quantum dots (QDs) are promising down-conversion phosphors for white light LEDs. However, the mainstream InP QDs synthesis uses expensive phosphorus source. Here, economic, in situ-generated PH3 is used to synthesize InP QDs and a two-step coating of ZnS shells is developed to prepare highly luminescent InP/ZnS/ZnS QDs. The QDs show a photoluminescence quantum yield as high as 78.5%. The emission can be tuned by adjusting the halide precursor and yellow emissive InP/ZnS/ZnS QDs are prepared by judiciously controlling the synthetic conditions. The yellow QDs show suppressed thermal quenching and retain &gt, 90% room temperature PL intensity at 150 °C for the growth solution. Additionally, the PL spectrum matches with the eye sensitivity function, resulting in efficient InP QD white light LEDs.

Growth of high-quality III–V nanowires at a low cost for optoelectronic and electronic applications is a long-term pursuit of research. Still, controlled synthesis of III–V nanowires using chemical vapor deposition method is challenge and lack theory guidance. Here, we show the growth of InP and GaP nanowires in a large area with a high density using a vacuum chemical vapor deposition method. It is revealed that high growth temperature is required to avoid oxide formation and increase the crystal purity of InP nanowires. Introduction of a small amount of Ga into the reactor leads to the formation of GaP nanowires instead of ternary InGaP nanowires. Thermodynamic calculation within the calculation of phase diagrams (CALPHAD) approach is applied to explain this novel growth phenomenon. Composition and driving force calculations of the solidification process demonstrate that only 1 at.% of Ga in the catalyst is enough to tune the nanowire formation from InP to GaP, since GaP nucleation shows a much larger driving force. The combined thermodynamic studies together with III–V nanowire growth studies provide an excellent example to guide the nanowire growth. Supplementary Information The online version contains supplementary material available at 10.1186/s11671-021-03505-2.

Simulations predict perfect phasematching for difference frequency generation (DFG) in a nonlinear ridge waveguide. It makes use of InGaAsP lattice-matched to InP as a nonlinear ridge waveguide. Both crystals possess high second-order susceptibility χ(2) and low loss, making them ideal for second-order nonlinear effects. The design allows two lasers in the telecom spectrum to interact in the nonlinear waveguide and emit in the mid-infrared (mid-IR). The InGaAsP ridge waveguide heterogeneously integrated on silicon-rich silicon nitride achieves phase-matching, resulting in a conversion efficiency η = 4.5 %/W.

We are reporting an esoteric method to determine the optical bandgap of direct gap materials by employing Urbach’s rule. The latter, which describes the slope of the band tail absorption in semiconductors, in its original version, cannot be employed to pinpoint the optical bandgap. Herein, however, we show that a modified form of Urbach’s rule defines the optical bandgap, and therefore, enables the accurate determination of the optical bandgap energy, which turns out to be identical with the threshold energy for the band tail absorption. The model further produces an explicit expression for the absorption coefficient at the optical bandgap energy.

This paper presents an overview of a sub-orbital flight demonstration with a 183 GHz and 540–600 GHz limb-sounding instrument aboard a stratospheric ballooncraft. The 183 GHz band provides soundings of stratospheric H 2 O and is implemented with a hybrid CMOS-InP receiver architecture which provides excellent sensitivity while remaining compact (162 g) and offering an extremely low DC power consumption (0.62 W). The 540–600 GHz channel sounds stratospheric O 3 and uses a combination of a CMOS local oscillator, GaAs Schottky mixer and micro-electro-mechanical-system (MEMS) RF switch for calibration, again offering competitive form factor (1.4 Kg) and low DC power consumption (6.6 W) compared to prior instruments. The instrument was flown on the NASA Reck-Tang Limb-sounding Experiment (ReckTangLE) ballooncraft and performed atmospheric soundings across New Mexico and Northwestern Texas on Oct. 17 2019.

This paper presents the results of the development of a technology for manufacturing electro-optical Mach–Zehnder modulators based on InP. The key features of the technology are the use of one SiNx double-patterned dielectric mask with two sequential inductively coupled plasma (ICP) etchings of the heterostructure for the simultaneous formation of active and passive sections of the modulator’s optical waveguides. This prevents misalignment errors at the borders. The planarization of the wafer surface was performed using photosensitive benzocyclobutene (BCB) films in a combined scheme. Windows in the BCB film to the bottom ohmic contact and at the die boundaries were formed by lithography, and then the excess thickness of the BCB film was removed by ICP etching until the p-InGaAs contact regions of the p-i-n heterostructure were exposed. The deposition and annealing of the top ohmic contact Ti/Pt/Au (50/25/400 nm) to p-InGaAs was carried out after the surface planarization, with the absence of both deformation and cracking of the planarizing film. A new approach to the division of the wafers into single dies is presented in this paper. The division was carried out in two stages: first, grooves were formed by dicing or deep wet etching, and then cleaving was performed along the formed grooves. The advantages of these techniques are that it allows the edges of the waveguides at the optical input/outputs to be formed and the antireflection coating to be deposited simultaneously on all dies on the wafer, before it is divided.

Design and simulations of an integrated photonic device that can optically detect the magnetization direction of its ultra-thin (&sim, 12 nm) metal cladding, thus &lsquo, reading&rsquo, the stored magnetic memory, are presented. The device is an unbalanced Mach Zehnder Interferometer (MZI) based on InP Membrane on Silicon (IMOS) platform. The MZI consists of a ferromagnetic thin-film cladding and a delay line in one branch, and a polarization converter in the other. It quantitatively measures the non-reciprocal phase shift caused by the Magneto-Optic Kerr Effect in the guided mode which depends on the memory bit&rsquo, s magnetization direction. The current design is an analytical tool for research exploration of all-optical magnetic memory reading. It has been shown that the device is able to read a nanoscale memory bit (400 &times, 50 &times, 12 nm) by using a Kerr rotation as small as 0.2∘, in the presence of a noise &sim, 10 dB in terms of signal-to-noise ratio. The device is shown to tolerate performance reductions that can arise during the fabrication.

Nominal dopant-free zinc blende twinning superlattice InP nanowires have been grown with high crystal-quality and taper-free morphology. Here, we demonstrate its superior optical performance and clarify the different carrier recombination mechanisms at different temperatures using a time resolved photoluminescence study. The existence of regular twin planes and lateral overgrowth do not significantly increase the defect density. At room temperature, the as-grown InP nanowires have a strong emission at 1.348 eV and long minority carrier lifetime (∼3 ns). The carrier recombination dynamics is mainly dominated by nonradiative recombination due to surface trapping states; a wet chemical etch to reduce the surface trapping density thus boosts the emission intensity and increases the carrier lifetime to 7.1 ns. This nonradiative recombination mechanism dominates for temperatures above 155 K, and the carrier lifetime decreases with increasing temperature. However, radiative recombination dominates the carrier dynamics at temperature below ∼75 K, and a strong donor-bound exciton emission with a narrow emission linewidth of 4.5 meV is observed. Consequently, carrier lifetime increases with temperature. By revealing carrier recombination mechanisms over the temperature range 10-300 K, we demonstrate the attraction of using InP nanostructure for photonics and optoelectronic applications.

Nano-ridge engineering (NRE) is a novel heteroepitaxial approach for the monolithic integration of lattice-mismatched III-V devices on Si substrates. It has been successfully applied to GaAs for the realization of nano-ridge (NR) laser diodes and heterojunction bipolar transistors on 300 mm Si wafers. In this report we extend NRE to GaSb for the integration of narrow bandgap heterostructures on Si. GaSb is deposited by selective area growth in narrow oxide trenches fabricated on 300 mm Si substrates to reduce the defect density by aspect ratio trapping. The GaSb growth is continued and the NR shape on top of the oxide pattern is manipulated via NRE to achieve a broad (001) NR surface. The impact of different seed layers (GaAs and InAs) on the threading dislocation and planar defect densities in the GaSb NRs is investigated as a function of trench width by using transmission electron microscopy (TEM) as well as electron channeling contrast imaging (ECCI), which provides significantly better defect statistics in comparison to TEM only. An InAs/GaSb multi-layer heterostructure is added on top of an optimized NR structure. The high crystal quality and low defect density emphasize the potential of this monolithic integration approach for infrared optoelectronic devices on 300 mm Si substrates.

This work explores the possibility of increasing the photovoltaic efficiency of InP semiconductors through a hyperdoping process with transition metals (TM = Ti, V, Cr, Mn). To this end, we investigated the crystal structure, electronic band and optical absorption features of TM-hyperdoped InP (TM@InP), with the formula TMxIn1-xP (x = 0.03), by using accurate ab initio electronic structure calculations. The analysis of the electronic structure shows that TM 3d-orbitals induce new states in the host semiconductor bandgap, leading to improved absorption features that cover the whole range of the sunlight spectrum. The best results are obtained for Cr@InP, which is an excellent candidate as an in-gap band (IGB) absorber material. As a result, the sunlight absorption of the material is considerably improved through new sub-bandgap transitions across the IGB. Our results provide a systematic and overall perspective about the effects of transition metal hyperdoping into the exploitation of new semiconductors as potential key materials for photovoltaic applications.

Indium phosphide quantum dots (QDs) have drawn attention as alternatives to cadmium- and lead-based QDs that are currently used as phosphors in lamps and displays. The main drawbacks of InP QDs are, in general, a lower photoluminescence quantum yield (PLQY), a decreased color purity, and poor chemical stability. In this research, we attempted to increase the PLQY and stability of indium phosphide QDs by developing lattice matched InP/MgSe core-shell nanoheterostructures. The choice of MgSe comes from the fact that, in theory, it has a near-perfect lattice match with InP, provided MgSe is grown in the zinc blende crystal structure, which can be achieved by alloying with zinc. To retain lattice matching, we used Zn in both the core and shell and we fabricated InZnP/ZnxMg1-xSe core/shell QDs. To identify the most suitable conditions for the shell growth, we first developed a synthesis route to ZnxMg1-xSe nanocrystals (NCs) wherein Mg is effectively incorporated. Our optimized procedure was employed for the successful growth of ZnxMg1-xSe shells around In(Zn)P QDs. The corresponding core/shell systems exhibit PLQYs higher than those of the starting In(Zn)P QDs and, more importantly, a higher color purity upon increasing the Mg content. The results are discussed in the context of a reduced density of interface states upon using better lattice matched ZnxMg1-xSe shells.

Significance A method is developed for enabling direct growth of shape-controlled single-crystal III–Vs on a wide range of substrates, including amorphous and/or low thermal budget substrates. Integration onto such substrates was previously limited by the high growth temperatures and lattice-match requirements of traditional deposition processes. Single-crystalline InP patterns are grown with substrate temperatures down to 220 °C by employing a templated liquid-phase crystallization method. InP grown by this method exhibits high electron mobilities and good optoelectronic properties, as demonstrated by the fabrication of high-performance transistors and light-emitting devices. The growth mode presents important practical implications for a broad spectrum of applications, as high-quality III–Vs can now be grown on virtually any substrate., III–V compound semiconductors are widely used for electronic and optoelectronic applications. However, interfacing III–Vs with other materials has been fundamentally limited by the high growth temperatures and lattice-match requirements of traditional deposition processes. Recently, we developed the templated liquid-phase (TLP) crystal growth method for enabling direct growth of shape-controlled single-crystal III-Vs on amorphous substrates. Although in theory, the lowest temperature for TLP growth is that of the melting point of the group III metal (e.g., 156.6 °C for indium), previous experiments required a minimum growth temperature of 500 °C, thus being incompatible with many application-specific substrates. Here, we demonstrate low-temperature TLP (LT-TLP) growth of single-crystalline InP patterns at substrate temperatures down to 220 °C by first activating the precursor, thus enabling the direct growth of InP even on low thermal budget substrates such as plastics and indium-tin-oxide (ITO)–coated glass. Importantly, the material exhibits high electron mobilities and good optoelectronic properties as demonstrated by the fabrication of high-performance transistors and light-emitting devices. Furthermore, this work may enable integration of III–Vs with silicon complementary metal-oxide-semiconductor (CMOS) processing for monolithic 3D integrated circuits and/or back-end electronics.

Recently a novel photonic integration technology, based on a thin InP-based membrane, is emerging. This technology offers monolithic integration of active and passive functions in a sub-micron thick membrane. The enhanced optical confinement in the membrane results in ultracompact active and passive devices. The membrane also enables approaches to converge with electronics. It has shown high potential in breaking the speed, energy and density bottlenecks in conventional photonic integration technologies. This paper explains the concept of the InP membrane, discusses the versatility of various technology approaches and reviews the recent advancement in this field.

Through the synthetic development of sophisticated core/shell heterostructures, the fluorescent properties of quantum dots (QDs) have been steadily improved to a level that can ultimately meet the industrial demands, but their reliability is still insufficient, particularly showing low fluorescence stability against degradable conditions. As one solution to this issue, an additional physical barrier typically with an oxide phase has been introduced to protect the QD surface from the environment. In this work, a strategy for improving the stability of QDs involving the passivation of their surfaces with zirconium propoxide (Zr(PrO)4) is suggested. Multi-shelled green QDs of InP/ZnSeS/ZnS were first synthesized, and then their surfaces were in-situ-treated with Zr(PrO)4. To confirm the presence of Zr(PrO)4-derived species on the QD surfaces, chemical analyses of the Zr(PrO)4-treated QDs were performed through Fourier transform infrared, X-ray photoelectron, and inductively coupled plasma optical emission spectroscopic measurements. A photostability test of two comparative InP/ZnSeS/ZnS QDs – one treated without and one with Zr(PrO)4 – was performed by exposing their dispersions to ultraviolet (UV) irradiation for prolonged periods of time, up to 120 h. It was revealed that Zr(PrO)4 treatment is highly effective in improving fluorescence retention and colloidal stability.

Semiconductor nanowire (NW) solar cells with a single p-n junction have exhibited efficiency comparable to that of their planar counterparts with a substantial reduction in material consumption. Tandem geometry is a path toward the fabrication of devices with even higher efficiencies, for which a key step is the fabrication of tunnel (Esaki) diodes within NWs with the correct diameter, pitch, and material combination for maximized efficiency. InP/GaInP and GaInP/InP NW tunnel diodes with band gap combinations corresponding to high-efficiency solar energy harvesting were fabricated and their electrical characteristics and material properties were compared. Four different configurations, with respect to material composition and doping, were investigated. The NW arrays were grown with metal–organic vapor-phase epitaxy from Au particles by use of nano-imprint lithography, metal evaporation and lift-off. Electrical measurements showed that the NWs behave as tunnel diodes in both InP (bottom)/GaInP (top) and GaInP (bottom)/InP (top) configurations, exhibiting a maximum peak current density of 25 A/cm2, and maximum peak to valley current ratio of 2.5 at room temperature. The realization of NW tunnel diodes in both InP/GaInP and GaInP/InP configurations represent an opportunity for the use of NW tandem solar cells, whose efficiency is independent of the growth order of the different materials, increasing the flexibility regarding dopant incorporation polarity. [Figure not available: see fulltext.]

InP-based HEMTs with composite GaInAs/InAs channels are recognized for their high frequency performance thanks to their superior carrier transport properties. On the other hand, the addition of an InP subchannel to a GaInAs channel can effectively suppress channel impact ionization, lower the output conductance, and improve noise properties. Although the literature provides a number of reports about both separate approaches, we merge both strategies in the present study and report the first GaInAs/InAs/InP composite channel HEMTs. The influence of the InAs inset location is studied through DC, RF and noise characterization. Devices with the InAs inset located further from the top AlInAs barrier exhibit an improved minimum noise figure NFMIN due to a reduced gate leakage current. The NFMIN improvement is accompanied by a slight degradation in both the output characteristics and cutoff frequencies resulting from the increased average gate-to-2DEG separation. Our results indicate that the combination of an InAs inset and an InP subchannel opens promising HEMT design avenues for broadband low-noise applications.

This paper presents a novel front-illuminated InAlAs/InGaAs separate absorption, grading, field-control and multiplication (SAGFM) avalanche photodiodes (APDs) with a mesa-structure for high speed response. The electric fields in the InAlAs-multiplication layer and InGaAs-absorption layer enable high multiplication gain and high-speed response thanks to the thickness and concentration of the field-control and multiplication layers. A mesa active region of 45 micrometers was defined using a bromine-based isotropic wet etching solution. The side walls of the mesa were subjected to sulfur treatment before being coated with a thick polyimide layer to reduce current leakage, while lowering capacitance and increasing response speeds. The breakdown voltage (VBR) of the proposed SAGFM APDs was approximately 32 V. Under reverse bias of 0.9 VBR at room temperature, the proposed device achieved dark current of 31.4 nA, capacitance of 0.19 pF and multiplication gain of 9.8. The 3-dB frequency response was 8.97 GHz and the gain-bandwidth product was 88 GHz. A rise time of 42.0 ps was derived from eye-diagrams at 0.9 VBR. There was notable absence of intersymbol-interference and the signals remained error-free at data-rates of up to 12.5 Gbps.

We demonstrate the generation of radio-frequency (RF) signals using stabilized integrated semiconductor lasers. The lasers are monolithically integrated on the same chip using InP active-passive integration technology. They are locked to different resonances of the same external optical cavity using the Pound-Drever-Hall locking technique. The locking is implement with single control loop for each laser and by voltage controlled tuning thus avoiding significant thermal effects. The generated RF signal can be tuned discretely to frequencies that are multiples of the external optical cavity free spectral range. Examples of beat tones at 12.436, 24.8735 and 40.4194 GHz are demonstrated. The linewidth of the generated signals at all frequencies is less than 40 kHz. The single-side-band phase noise is about -54 dBc/Hz for frequencies offsets from the carrier at 12.436 GHz between 1 kHz and 10 kHz and -60 and -67 dBc/Hz at 100 kHz and 1 MHz respectively.

Residual amplitude modulation of the phase modulator deployed in Pound-Drever-Hall frequency stabilization is an effect known to cause instabilities to the absolute wavelength of the stabilized laser. We present measurements and analysis of the residual amplitude modulation in an InP-based waveguide electro-optic phase modulator. The modulator is monolithically integrated in the output waveguide of a tuneable laser. The effects on the frequency stabilization of such a laser system to a reference etalon using a Pound-Drever-Hall frequency stabilization scheme are quantified. Frequency offset values in the stabilization point from the reference Fabry-Perot etalon resonance caused by the amplitude modulation are predicted and optimum operating points to minimize residual amplitude modulation are discussed. By operating an electro-refractive phase modulator at the proper bias point we show that frequency offsets corresponding to less than 3×10 ^{-3}$ of the reference cavity full-width half-maximum can be achieved.

© 2018 Elsevier B.V. Quantum Dots (QDs) are considered as an efficient building block of many optoelectronic applications, such as semiconductor laser, photodetector, whereby their physical dimension is the key parameter to be controlled. In this work, we have studied experimentally the growth of InAs QDs on InP(0 0 1) substrate by MOVPE and established a theoretical model explaining the observed epitaxial behaviour. In variance with the classical Stranski-Krastanov growth, we show that during the growth there is an intermediate stage whereby although first large 3D islands are formed, an increased density of small QDs is formed concurrent with the shrinkage of the large 3D islands. As a result, the growth can be divided into three regimes: 2D layer growth, large 3D islands growth and QDs growth. To explain this evolution, a thermodynamic model has been developed accounting for the process driven by surface energy, elastic relaxation energy and inter-island interaction energy. It will be shown that the balance between the surface energy and the elastic relaxation energy provides the transition from 2D layer to large 3D islands (around at 3 ML of InAs growth). This model also supports the energetically favourable truncated pyramidal shape for large 3D islands and the spherical cap shape for QDs. We show in this paper that a balance between surface energy, elastic relaxation energy and inter-island elastic interaction explains the volume shrinkage of the early large 3D islands towards the formation of small QDs in high density. ispartof: JOURNAL OF CRYSTAL GROWTH vol:509 pages:133-140 status: published

Indium-Phosphide (InP) is one of the most common materials used for realizing active devices working in the millimeter frequency range. The isotropic etching profile of InP substrates limits the realization of passive devices, thus requiring an expensive and lossy hybrid platform. This paper presents a via-less, cost-effective and efficient solution for InP substrate. By using the proposed planar solution, it is demonstrated that rectangular waveguides can be realized on InP by fabricating a bed of nails structure which acts as a reflecting boundary for an impinging millimeter wave. As a proof of concept, a transition from microstrip to rectangular waveguide structure is realized within H-band (220-320 GHz) with a return loss of -18dB over a bandwidth of 30 GHz.

An environment-friendly inverted indium phosphide red quantum dot light-emitting diode (InP QLED) was fabricated using Mg-doped zinc oxide (ZnMgO) as the electron transport layer (ETL). The effects of ZnMgO ETL on the performance of InP QLED were investigated. X-ray diffraction (XRD) analysis indicated that ZnMgO film has an amorphous structure, which is similar to zinc oxide (ZnO) film. Comparison of morphology between ZnO film and ZnMgO film demonstrated that Mg-doped ZnO film remains a high-quality surface (root mean square roughness: 0.86 nm) as smooth as ZnO film. The optical band gap and ultraviolet photoelectron spectroscopy (UPS) analysis revealed that the conduction band of ZnO shifts to a more matched position with InP quantum dot after Mg-doping, resulting in the decrease in turn-on voltage from 2.51 to 2.32 V. In addition, the ratio of irradiation recombination of QLED increases from 7% to 25% using ZnMgO ETL, which can be attributed to reduction in trap state by introducing Mg ions into ZnO lattices. As a result, ZnMgO is a promising material to enhance the performance of inverted InP QLED. This work suggests that ZnMgO has the potential to improve the performance of QLED, which consists of the ITO/ETL/InP QDs/TCTA/MoO3/Al, and Mg-doping strategy is an efficient route to directionally regulate ZnO conduction bands.

This is the first demonstration of sidewall slope control of InP via holes with an etch depth of more than 10 &mu, m for 3D integration. The process for the InP via holes utilizes a common SiO2 layer as an InP etch mask and conventional inductively coupled plasma (ICP) etcher operated at room temperature and simple gas mixtures of Cl2/Ar for InP dry etch. Sidewall slope of InP via holes is controlled within the range of 80 to 90 degrees by changing the ICP power in the ICP etcher and adopting a dry-etched SiO2 layer with a sidewall slope of 70 degrees. Furthermore, the sidewall slope control of the InP via holes in a wide range of 36 to 69 degrees is possible by changing the RF power in the etcher and introducing a wet-etched SiO2 layer with a small sidewall slope of 2 degrees, this wide slope control is due to the change of InP-to-SiO2 selectivity with RF power.

In(Ga)As/GaAs-based quantum dot infrared photodetectors (QDIPs) are among the most efficient devices in the mid-wavelength infrared and long-wavelength infrared regions for various defense and space application purposes. Considering the importance of the results reported so far on In(Ga)As/GaAs QDIPs, here we had tried to develop a post-growth method for enhancing QDIP characteristics using both low energy and high energy light ion (hydrogen) implantations. The field-assisted tunneling process of dark current generation was suppressed due to the hydrogen ion implantation, even at a very high operational bias. A stronger multicolor photo-response was obtained for devices implanted with low energy hydrogen ions. From experimental results, we proposed a device model which explains the improved QDIPs performance caused by hydrogen ion implantation. (C) 2016 Elsevier Ltd. All rights reserved.

Three different types of samples of InP nanowires, i.e. undoped, doped with Si and doped with Te, were grown and measured using SEM and Raman spectroscopy. Scanning Electron Microscope (SEM) images showed differences in the length, homogeneity and curvature of the nanowires. The most homogenous wires, grown most perpendicular to the surface, were those Si doped. They were also the shortest. Raman spectroscopy showed that the nanowires doped with Si had the lowest Full Width at Half Maximum (FWHM) TO band, which suggests the highest crystal quality of these wires. For the wires doped with Te, which were the most inhomogeneous, a low energy acoustic band was also observed, which suggests the lowest crystal quality of these structures.

This letter describes the reduction of optical crosstalk by means of focused ion beam-etched trenches in InGaAs/InP single-photon avalanche diode arrays. Platinum-filled trenches have been fabricated in a linear array in order to limit the direct optical crosstalk between neighboring pixels. Experimental measurements prove that optical crosstalk has been reduced by $\sim 60$ % thanks to a strong suppression of direct optical paths. An optical model is introduced in order to describe the main contributions to crosstalk and to validate measurements.

In this paper, the microwave characteristic of photosensitive material InP irradiated by different optical signals is studied based on the coaxial resonant cavity. The coaxial resonant cavity sensor has an operating frequency range from 1 to 4 GHz, an operating mode of TEMn/4, and a quality factor of 8000 or more. According to the theory of semiconductor and electromagnetic field, the equation describing the relationship between the irradiation power and the quality factor of the coaxial resonator is derived. Additionally, in the short-time irradiation experiment, the variation of microwave characteristics of InP with irradiation power of 10mW, 50mW, 100mW, and 250mW is studied by frequency-domain and time-domain scanning methods, respectively. The measurement results indicate that the microwave characteristic variation of the InP under short-time weak power irradiation is mainly caused by the non-thermal effect, while the thermal effect is not obvious. In order to investigate the influence of thermal effect on the microwave characteristic of InP under continuous illumination, taking the irradiation power of 100mW as an example, the irradiation experiment with a duration of 1 min is performed on the InP. The thermal and non-thermal effects at the moment of opening and closing of the monochrome light source and during irradiation are analyzed. Furthermore, the stability and response speed of the system are analyzed and tested, and the measurement results are in good agreement with the theoretical analysis.

Graphical abstract, Highlights • InP-In2O3 QDs are synthesized by a single-step chemical method without injection of hot precursors. • HR-TEM images show the synthesis of InP and In2O3 QDs. • The InP and In2O3 QDs size increases with the P(TMS)3 concentration. • PL spectra reveal emission bands attributed to InP and In2O3 QDs. • XPS confirms the formation of InP, In2O3 and amorphous InPOx., InP-In2O3 colloidal quantum dots (QDs) synthesized by a single-step chemical method without injection of hot precursors (one-pot) were investigated. Specifically, the effect of the tris(trimethylsilyl)phosphine, P(TMS)3, precursor concentration on the QDs properties was studied to effectively control the size and shape of the samples with a minimum size dispersion. The effect of the P(TMS)3 precursor concentration on the optical, structural, chemical surface, and electronic properties of InP-In2O3 QDs is discussed. The absorption spectra of InP-In2O3 colloids, obtained by both UV–Vis spectrophotometry and photoacoustic spectroscopy, showed a red-shift in the high-energy regime as the concentration of the P(TMS)3 increased. In addition, these results were used to determine the band-gap energy of the InP-In2O3 nanoparticles, which changed between 2.0 and 2.9 eV. This was confirmed by Photoluminescence spectroscopy, where a broad-band emission displayed from 2.0 to 2.9 eV is associated with the excitonic transition of the InP and In2O3 QDs. In2O3 and InP QDs with diameters ranging approximately from 8 to 10 nm and 6 to 9 nm were respectively found by HR-TEM. The formation of the InP and In2O3 phases was confirmed by X-ray Photoelectron Spectroscopy.

We study the size-dependent optical properties of periodic arrays of semiconducting nanolines in the near-infrared to near-ultraviolet spectral range, where the absorption of the semiconductor increases. Using band structure calculations, we demonstrate that specific dimensions allow the slow down of the light, resulting in an enhanced absorption as compared to bulk material once the extinction coefficient of the semiconductor becomes comparable to its refractive index. Further, the refractive properties of the arrays can be tailored beyond the values of the constituting materials when the extinction coefficient of the semiconductor exceeds its refractive index. To confirm our theoretical findings, we propose a simple semi-analytical model for the light interactions with such structures and validate it with experimental reflectance spectra collected on arrays for the next-generation transistors. ispartof: OPTICS EXPRESS vol:28 issue:5 pages:6781-6793 ispartof: location:United States status: published

We demonstrate a monolithic extended cavity InP-based single-mode laser with DBR mirrors and an intra-cavity ring resonator with 15 mA threshold current fabricated with a generic integration technology. A 130 kHz linewidth has been measured and an SMSR well over 60dB.

III−V solar cells in the nanowire geometry mighth old significant synthesis-cost and device-design advantages as compared to thin films and have shown impressive performance improvements in recent years. To continue this development there is a need for characterization techniques giving quick and reliable feedback for growth development. Further, characterization techniques which can improve understanding of the link between nanowire growth conditions, subsequent processing, and solar cell performance are desired. Here, we present the use of a nanoprobe system inside a scanning electron microscope to efficiently contact single nanowires and characterize them in terms of key parameters for solar cell performance. Specifically, we study single as-grown InP nanowires and use electron beam induced current characterization to understand the charge carrier collection properties, and dark current−voltage characteristics to understand the diode recombination characteristics. By correlating the single nanowire measurements to performance of fully processed nanowire array solar cells, we identify how the performance limiting parameters are related to growth and/or processing conditions. We use this understanding to achieve a more than 7-fold improvement in efficiency of our InP nanowire solar cells, grown from a different seed particle pattern than previously reported from our group. The best cell shows a certified efficiency of 15.0%; the highest reported value for a bottom-up synthesized InP nanowire solar cell. We believe the presented approach have significant potential to speed-up the development of nanowire solar cells, as well as other nanowire-based electronic/optoelectronic devices.

International audience; The properties of semiconductors can be controlled using doping, making it essential for electronic and optoelectronic devices. However, with shrinking device sizes it becomes increasingly difficult to quantify doping with sufficient sensitivity and spatial resolution. Here, we demonstrate how X-ray fluorescence mapping with a nanofocused beam, nano-XRF, can quantify Zn doping within in situ doped III-V nanowires, by using large area detectors and high-efficiency focusing optics. The spatial resolution is defined by the focus size to 50 nm. The detection limit of 7 ppm (2.8 X 10(17) cm(-3)), corresponding to about 150 Zn atoms in the probed volume, is bound by a background signal. In solar cell InP nanowires with a p-i-n doping profile, we use nano-XRF to observe an unintentional Zn doping of 5 x 10(17) cm(-3) in the middle segment. We investigated the dynamics of in situ Zn doping in a dedicated multisegment nanowire, revealing significantly sharper gradients after turning the Zn source off than after turning the source on. Nano-XRF could be used for quantitative mapping of a wide range of dopants in many types of nanostructures.

We explore conditions for achieving laser liftoff in epitaxially grown heterojunctions, in which single crystal thin films can be separated from their growth substrates using a selectively absorbing buried intermediate layer. Because this highly non-linear process is subject to a variety of process instabilities, it is essential to accurately characterize the parameters resulting in liftoff. Here, we present an InP/InGaAs/InP heterojunction as a model system for such characterization. We show separation of InP thin films from single crystal InP growth substrates, wherein a ≈10 ns, Nd:YAG laser pulse selectively heats a coherently strained, buried InGaAs layer. We develop a technique to measure liftoff threshold fluences within an inhomogeneous laser spatial profile, and apply this technique to determine threshold fluences of the order 0.5 J cm −2 for our specimens. We find that the fluence at the InGaAs layer is limited by non-linear absorption and InP surface damage at high powers, and measure the energy transmission in an InP substrate from 0 to 8 J cm −2. Characterization of the ejected thin films shows crack-free, single crystal InP. Finally, we present evidence that the hot InGaAs initiates a liquid phase front that travels into the InP substrate during liftoff.

Highly ordered gallium indium phosphide layers with the low bandgap have been successfully grown on the (100) GaAs substrates, the misorientation toward [01-1] direction, using the low-pressure metal organic chemical vapor deposition method. It is found that the optical properties of the layers are same as those of the disordered ones, essentially different from the ordered ones having two orientations towards [1-11] and [11-1] directions grown on (100) gallium arsenide substrates, which were previously reported. The bandgap at 300 K is 1.791 eV. The value is the smallest ever reported, to our knowledge. The high performance transverse stabilized AlGaInP laser diodes with strain compensated quantum well structure, which is developed in 1992, have been successfully obtained by controlling the misorientation angle and directions of GaAs substrates. The structure is applied to quantum dots laser diodes. This paper also describes the development history of the quantum well and the quantum dots laser diodes, and their future prospects.

International audience; We report on a new cost effective, with a low temperature budget and simple bonding process on silicon, presenting efficient heat spreading and great potentialities in integration. This process is based on a thick electro-plated copper bonding layer through silicon vias and is expected to reduce significantly the bonded device internal temperature. We apply this process to realize 1.55-μm emitting vertical-cavity surface-emitting lasers. We demonstrate continuous wave operation from room temperature up to 55 °C, an internal temperature reduction of 13 °C, and we estimate a decrease of 30% of the overall device thermal impedance.

International audience; The metallurgical properties of the Ti/InP system meet a great interest for its use as a contact in the scope of various applications such as the Si Photonics. The investigations conducted on this system highlight the initiation of a reaction between the Ti and the InP substrate during the deposition process conducted at 100 °C. The simultaneous formation of two binary phases, namely, Ti$_2$In$_5$ and TiP, is attributed to the compositional gradient induced in the InP by the wet surface preparation and enhanced by the subsequent $in situ$ Ar$^+$ preclean. Once formed, the TiP layer acts as a diffusion barrier inhibiting further reaction up to 450 °C in spite of the presence of an important Ti reservoir. At higher temperature, however, i.e., from 550 °C, the reaction is enabled either by the enhancement of the species diffusion through the TiP layer or by its agglomeration. This reaction gives rise to the total consumption of the Ti$_2$In$_5$ and Ti while the TiP and In phases are promoted.