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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on InAs by Materials Project

InAs crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent In3+ sites. In the first In3+ site, In3+ is bonded to five As3- atoms to form distorted InAs5 trigonal bipyramids that share corners with five equivalent InAs5 trigonal bipyramids, edges with four equivalent InAs6 octahedra, and edges with four equivalent InAs5 trigonal bipyramids. There are a spread of In–As bond distances ranging from 2.84–3.07 Å. In the second In3+ site, In3+ is bonded to six As3- atoms to form InAs6 octahedra that share corners with four equivalent InAs6 octahedra, edges with four equivalent InAs6 octahedra, and edges with eight equivalent InAs5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of In–As bond distances ranging from 2.86–3.15 Å. There are two inequivalent As3- sites. In the first As3- site, As3- is bonded in a 6-coordinate geometry to five In3+ and one As3- atom. The As–As bond length is 2.53 Å. In the second As3- site, As3- is bonded to six In3+ atoms to form a mixture of edge and corner-sharing AsIn6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba2(InAs)5 by Materials Project

Ba2(InAs)5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to seven As3- atoms to form distorted BaAs7 pentagonal bipyramids that share a cornercorner with one InAs4 tetrahedra, edges with four BaAs7 pentagonal bipyramids, edges with two equivalent InAs4 tetrahedra, and faces with two equivalent BaAs7 pentagonal bipyramids. There are a spread of Ba–As bond distances ranging from 3.35–3.40 Å. In the second Ba2+ site, Ba2+ is bonded to seven As3- atoms to form distorted BaAs7 pentagonal bipyramids that share corners with three equivalent InAs4 tetrahedra, edges with six BaAs7 pentagonal bipyramids, and an edgeedge with one InAs4 tetrahedra. There are a spread of Ba–As bond distances ranging from 3.38–3.59 Å. There are five inequivalent In+2.20+ sites. In the first In+2.20+ site, In+2.20+ is bonded to four As3- atoms to form InAs4 tetrahedra that share corners with four BaAs7 pentagonal bipyramids, corners with two equivalent InAs4 tetrahedra, and edges with three BaAs7 pentagonal bipyramids. There are a spread of In–As bond distances ranging from 2.73–2.75 Å. In the second In+2.20+ site, In+2.20+ is bonded in a trigonal non-coplanar geometry to three As3- atoms. There are one shorter (2.71 Å) and two longer (2.75 Å) In–As bond lengths. In the third In+2.20+ site, In+2.20+ is bonded in a trigonal non-coplanar geometry to three As3- atoms. There are two shorter (2.74 Å) and one longer (2.75 Å) In–As bond lengths. In the fourth In+2.20+ site, In+2.20+ is bonded in a trigonal non-coplanar geometry to three As3- atoms. There are two shorter (2.75 Å) and one longer (2.84 Å) In–As bond lengths. In the fifth In+2.20+ site, In+2.20+ is bonded in a trigonal non-coplanar geometry to three As3- atoms. There are two shorter (2.72 Å) and one longer (2.79 Å) In–As bond lengths. There are five inequivalent As3- sites. In the first As3- site, As3- is bonded to three Ba2+ and three In+2.20+ atoms to form a mixture of corner, edge, and face-sharing AsBa3In3 octahedra. The corner-sharing octahedra tilt angles range from 36–65°. In the second As3- site, As3- is bonded to three equivalent Ba2+ and three In+2.20+ atoms to form a mixture of corner, edge, and face-sharing AsBa3In3 octahedra. The corner-sharing octahedra tilt angles range from 15–68°. In the third As3- site, As3- is bonded to three equivalent Ba2+ and three In+2.20+ atoms to form a mixture of corner and edge-sharing AsBa3In3 octahedra. The corner-sharing octahedra tilt angles range from 25–55°. In the fourth As3- site, As3- is bonded to three Ba2+ and three In+2.20+ atoms to form a mixture of corner, edge, and face-sharing AsBa3In3 octahedra. The corner-sharing octahedra tilt angles range from 15–62°. In the fifth As3- site, As3- is bonded to two equivalent Ba2+ and four In+2.20+ atoms to form a mixture of corner and edge-sharing AsBa2In4 octahedra. The corner-sharing octahedra tilt angles range from 25–68°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on InAs by Materials Project

InAs is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. In3+ is bonded to four equivalent As3- atoms to form corner-sharing InAs4 tetrahedra. There are three shorter (2.68 Å) and one longer (2.69 Å) In–As bond lengths. As3- is bonded to four equivalent In3+ atoms to form corner-sharing AsIn4 tetrahedra.

36 MATERIALS SCIENCE↗
NASA NTRS2002

Improved dot size uniformity and luminescense of InAs quantum dots on InP substrate

InAs self-organized quantum dots have been grown in InGaAs quantum well on InP substrates by metalorganic vapor phase epitaxy. Atomic Force Microscopy confirmed of quantum dot formation with dot density of 3X10(sup 10) cm(sup -2). Improved dot size uniformity and strong room temperature photoluminescence up to 2 micron were observed after modifying the InGaAs well.

InAs quantum dot↗
DOE OSTI2024

Colloidal InAs Quantum Dot-Based Infrared Optoelectronics Enabled by Universal Dual-Ligand Passivation

Solution-processed low-bandgap semiconductors are crucial to next-generation infrared (IR) detection for various applications, such as autonomous driving, virtual reality, recognitions, and quantum communications. In particular, III–V group colloidal quantum dots (CQDs) are interesting as nontoxic bandgap-tunable materials and suitable for IR absorbers; however, the device performance is still lower than that of Pb-based devices. Herein, a universal surface-passivation method of InAs CQDs enabled by intermediate phase transfer (IPT), a preliminary process that exchanges native ligands with aromatic ligands on the CQD surface is presented. IPT yields highly stable CQD ink. In particular, desirable surface ligands with various reactivities can be obtained by dispersing them in green solvents. Furthermore, CQD near-infrared (NIR) photodetectors are demonstrated using solution processes. Careful surface ligand control via IPT is revealed that enables the modulation of surface-mediated photomultiplication, resulting in a notable gain control up to ≈10 with a fast rise/fall response time (≈12/36 ns). Considering the figure of merit (FOM), EQE versus response time (or –3 dB bandwidth), the optimal CQD photodiode yields one of the highest FOMs among all previously reported solution-processed nontoxic semiconductors comprising organics, perovskites, and CQDs in the NIR wavelength range.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Dislocation‐Induced Structural and Luminescence Degradation in InAs Quantum Dot Emitters on Silicon

This study probes the extent to which dislocations reduce carrier lifetimes and alter growth morphology and luminescence in InAs quantum dots (QD) grown on silicon. These heterostructures are key ingredients to achieving a highly reliable monolithically integrated light source on silicon necessary for photonic-integrated circuits. Around 20%–30% shorter carrier lifetimes are found at spatially resolved individual dislocations at room temperature using time-resolved cathodoluminescence spectroscopy, highlighting the strong nonradiative impact of dislocations even against the three-dimensional confinement of QDs. Beyond these direct effects of increased nonradiative recombination, it is found that misfit dislocations in the defect filter layers employed during III–V/Si growth alter the QD growth environment to induce a crosshatch-like variation in QD emission color and intensity when the filter layer is positioned sufficiently close to the QD emitter layer. Sessile threading dislocations generate even more egregious hillock defects that also reduce emission intensities by altering layer thicknesses, as measured by transmission electron microscopy and atom probe tomography. This work presents a more complete picture of the impacts of dislocations relevant to the development of light sources for scalable silicon photonic integrated circuits.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Carrier-Envelope Phase Control in Terahertz Pulse Generation Using InAs Ribbon Metasurfaces

Generation of broadband terahertz (THz) pulses with variable polarization and carrier-envelope phase can enable the tailoring of THz beam wavefronts for advanced applications in THz imaging and spectroscopy and for strong THz field optics. While metasurfaces composed of deeply subwavelength THz emitters have recently been demonstrated to define the polarization and spatial profile of the generated THz fields, precise phase control or synthesis of THz pulse waveforms remains a challenging problem. Here, we propose and demonstrate metasurfaces composed of indium arsenide (InAs) nanoscale ribbon arrays capable of generating THz pulses with variable carrier-envelope phase. We show that different THz generation mechanisms, each contributing distinct phases, can be activated in the ribbons, enabling carrier-envelope phase control spanning a range of π over a wide band of frequencies (∼1–3 THz). This is achieved solely through the ribbon array geometry using linearly polarized optical excitation of the ribbons. The arrays enable precise control of the THz phase and amplitude, opening the door to advanced structured THz wavefront synthesis using ultrathin dielectric metasurfaces.

carrier-envelope phase↗
DOE OSTI2023

Confinement of 1D Chain and 2D Layered CuI Modules in K-INA-R Frameworks via Coordination Assembly: Structure Regulation and Semiconductivity Tuning

Herein, we present a new series of CuI-based hybrid materials with tunable structures and semiconducting properties. Furthermore, the CuI inorganic modules can be tailored into a one-dimensional (1D) chain and two-dimensional (2D) layer and confined/stabilized in coordination frameworks of potassium isonicotinic acid (HINA) and its derivatives (HINA-R, R = OH, NO 2 , and COOH). The resulting CuI-based hybrid materials exhibit interesting semiconducting behaviors associated with the dimensionality of the inorganic module; for instance, the structures containing the 2D-CuI module demonstrate significantly enhanced photoconductivity with a maximum increase of five orders of magnitude compared to that of the structures containing the 1D-CuI module. They also represent the first CuI-bearing hybrid chemiresistive gas sensors for NO 2 with boosted sensing performance and sensitivity at multiple orders of magnitude over that of the pristine CuI. Particularly, the sensing ability of CuI-K-INA containing both 1D- and 2D-CuI modules is comparable to those of the best NO 2 chemiresistors reported thus far.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Observation of nonlocal Josephson effect on double InAs nanowires

Short-range coherent coupling of two Josephson junctions (JJs) are predicted to generate a supercurrent in one JJ nonlocally modulated by the phase difference in the other. We report on observation of the nonlocal Josephson effect on double InAs nanowires as experimental evidence of the coherent coupling. We measure one JJ sharing one superconducting electrode with the other JJ and observe switching current oscillation as a control of the nonlocal phase difference. Our result will contribute to engineer novel superconducting phenomena with the short-range coherent coupling.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Non-radiative recombination at dislocations in InAs quantum dots grown on silicon

We study the impact of misfit dislocations on the luminescence from InAs quantum dots (QDs) grown on Si substrates. Electron channeling contrast imaging is used together with cathodoluminescence mapping to locate misfit dislocations and characterize the resulting nonradiative recombination of carriers via near-infrared light emission profiles. With a 5 kV electron beam probe, the dark line defect width due to a typical misfit dislocation in a shallow QD active layer is found to be approximately 1 μ m, with a 40%–50% peak emission intensity loss at room temperature. Importantly, we find that at cryogenic temperatures, the dislocations affect the QD ground state and the first excited state emission significantly less than the second excited state emission. At the same time, the dark line defect width, which partially relates to carrier diffusion in the system, is relatively constant across the temperature range of 10 K–300 K. Our results suggest that carrier dynamics in the QD wetting layer control emission intensity loss at dislocations, and that these defects reduce luminescence only at those temperatures where the probability of carriers thermalizing from the dots into the wetting layer becomes significant. We discuss the implications of these findings toward growing dislocation-tolerant, reliable quantum dot lasers on silicon.

Electron beams↗
DOE OSTI2020

Recombination-enhanced dislocation climb in InAs quantum dot lasers on silicon

Here, we analyze the structure of dislocations in electrically aged InAs quantum dot (QD) lasers on silicon to understand gradual device degradation. We find that misfit dislocations lengthen due to carrier injection, experiencing a combination of recombination-enhanced climb and glide processes constrained by the epitaxial structure. An examination of the dislocation geometry reveals that the climb process involves the addition of atoms to the extra half plane of the dislocation. Spontaneous emission from the QDs is also dimmer after aging. Additionally, the signature of misfit dislocations in the unaged laser, discernible as sharp dark lines in spatially resolved cathodoluminescence, is replaced by finer, more inhomogeneous contrast upon aging. We speculate that this change arises from vacancy clouds expelled from the dislocation during climb. With this insight, we evaluate the driving forces for dislocation climb that could be at play and discuss the origins of slow degradation in QD lasers.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Current-phase relations of InAs nanowire Josephson junctions: From interacting to multimode regimes

Gate-tunable semiconductor-superconductor nanowires with superconducting leads form exotic Josephson junctions that are a highly desirable platform for two types of qubits: Those with topological superconductivity (Majorana qubits) and those based on tunable anharmonicity (gatemon qubits). Controlling their behavior, however, requires understanding their electrostatic environment and electronic structure. Here we study gated InAs nanowires with epitaxial aluminum shells. By measuring current-phase relations and comparing them with analytical and numerical calculations, we show that we can tune the number of modes, determine the transparency of each mode, and tune into regimes in which electron-electron interactions are apparent, indicating the presence of a quantum dot. To take into account electrostatic and geometrical effects, we perform microscopic self-consistent Schrodinger-Poisson numerical simulations, revealing the energy spectrum of Andreev states in the junction as well as their spatial distribution. Here, our work systematically demonstrates the effect of device geometry, gate voltage, and phase bias on mode behavior, providing insights into ongoing experimental efforts and predictive device design.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Origin of surface and subband states at the InAs(111)A surface

The atomic structure of surfaces and interfaces plays a vital role in the electronic quality and properties of quantum devices. The interplay between the surface and confined bulk subband states in terms of their susceptibility has been investigated in relation to crystal defects on an InAs(111)A-(2×2) reconstructed surface, using low-temperature scanning tunneling microscopy and spectroscopy. We measure the two-dimensional quantized subband states arising from the confined potential imposed by downward bending of the conduction band edge. Furthermore, we show evidence of the existence of surface Bloch states within the confined bulk band gap projected on the surface spectrum which have originated from the surface reconstruction. As expected, larger confined bulk band gaps at the surface and conduction band offset are measured to be 0.58 and 0.31 eV, respectively. Here we further show the scattering of these quantum states at different surface defects and demonstrate that surface states are more susceptible to the defect potential when compared with the corresponding subband states. This apparent contrast follows from the length scale at which these defect potentials actively interact on or near the surface. Our observed experimental results are supported by empirical tight-binding simulations for the subband states and first-principles density functional theory simulations for the surface states present on the surface.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Topological material in the III–V family: Heteroepitaxial InBi on InAs

InBi ( 0 0 1 ) is formed epitaxially on InAs ( 1 1 1 ) -A by depositing Bi onto an In-rich surface. Angle-resolved photoemission measurements reveal topological electronic surface states, close to the M ¯ high symmetry point. This demonstrates a heteroepitaxial system entirely in the III–V family with topological electronic properties. InBi shows coexistence of Bi and In surface terminations, in contradiction with other III–V materials. For the Bi termination, the study gives a consistent physical picture of the topological surface electronic structure of InBi ( 0 0 1 ) terminated by a Bi bilayer rather than a surface formed by splitting to a Bi monolayer termination. Theoretical calculations based on relativistic density functional theory and the one-step model of photoemission clarify the relationship between the InBi ( 0 0 1 ) surface termination and the topological surface states, supporting a predominant role of the Bi bilayer termination. Furthermore, a tight-binding model based on this Bi bilayer termination with only Bi–Bi hopping terms, and no Bi–In interaction, gives a deeper insight into the spin texture. Published by the American Physical Society 2024

Nicolaï, Laurent (ORCID:0000000277312673)↗
DOE OSTI2024

Picosecond carrier dynamics in InAs and GaAs revealed by ultrafast electron microscopy

Understanding the limits of spatiotemporal carrier dynamics, especially in III-V semiconductors, is key to designing ultrafast and ultrasmall optoelectronic components. However, identifying such limits and the properties controlling them has been elusive. Here, using scanning ultrafast electron microscopy, in bulk n-GaAs and p-InAs, we simultaneously measure picosecond carrier dynamics along with three related quantities: subsurface band bending, above-surface vacuum potentials, and surface trap densities. We make two unexpected observations. First, we uncover a negative-time contrast in secondary electrons resulting from an interplay among these quantities. Second, despite dopant concentrations and surface state densities differing by many orders of magnitude between the two materials, their carrier dynamics, measured by photoexcited band bending and filling of surface states, occur at a seemingly common timescale of about 100 ps. This observation may indicate fundamental kinetic limits tied to a multitude of material and surface properties of optoelectronic III-V semiconductors and highlights the need for techniques that simultaneously measure electro-optical kinetic properties.

42 ENGINEERING↗
DOE OSTI2019

InAs{sub (1 –} {sub y)}Sb{sub y}/InAsSbP Narrow-Gap Heterostructures (y = 0.09–0.16) Grown by Metalorganic Vapor Phase Epitaxy for the Spectral Range of 4–6 μm

Asymmetric n-InAs/InAs{sub (1 –} {sub y)}Sb{sub y}/p-InAsSbP heterostructures with a narrow-gap active layer and a composition range y = 0.09–0.16 were grown by vapor phase epitaxy from metalorganic compounds. Room-temperature electroluminescence was observed at a wavelength of up to λ = 5.1 μm at a spectral maximum. The study of low-temperature electroluminescence spectra provided the possibility to establish the existence of two radiative recombination channels caused by the nature of the InAsSb/InAsSbP heterointerface. The effect produced by the chemistry of the active layer on the composition of the grown barrier layer and the formation of the InAsSb/InAsSbP heterojunction with an increase in the antimony content in the InAsSb solid solution was demonstrated.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗