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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Ice Nucleating Particles (INP) Raw Data

The ice nucleation spectrometer (INS) is an offline analytical measurement system used to process filter samples for freezing temperature spectra of immersion-mode ice-nucleating particle (INP) number concentrations. It is almost identical to the Colorado State University (CSU) ice spectrometer design. Filter samples are collected at ARM facilities routinely and during intensive operational periods, and on the ARM tethered balloon system operated by Sandia National Laboratories, then processed on the INS at CSU. This filter log contains the detailed metadata at all ARM sites where INP filter sample collection has occurred or is currently ongoing. Metadata include start and end times, vacuum line pressures and temperatures, and flow rates; total accumulated flow through each filter; and notes on collection issues or weather conditions. Users can also keep up to date with the status of filter and data processing, even before data are available on ARM's Data Discovery. Users can contact INP mentors Jessie Creamean or Thomas Hill with any questions.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Ice-nucleating particles (INPs) concentrations from SAIL-Net

This data set contains ice-nucleating particle (INP) concentration spectra collected during the SAIL-Net sampling period, which complemented the Surface Atmosphere Integrated Field Laboratory (SAIL) campaign in the East River watershed near Crested Butte, Colorado. SAIL-Net was a distributed aerosol measurement network designed to investigate aerosol variability across complex mountainous terrain. The data set includes samples from multiple SAIL-Net sites, including AOS, Gothic, Snodgrass, Pumphouse, Irwin, and Top. INP concentrations are reported as a function of freezing temperature, together with confidence limits, sampling times, site location, elevation, sampled air volume, and treatment information. These data provide an analysis-ready record of the INPs across the SAIL-Net network.

activation temperature↗
DOE OSTI2024

Sub‐0.6 eV Inverted Metamorphic GaInAs Cells Grown on Inp and GaAs Substrates for Thermophotovoltaics and Laser Power Conversion

Abstract Inverted metamorphic Ga 0.3 In 0.7 As photovoltaic converters with sub‐0.60 eV bandgaps grown on InP and GaAs are presented. Threading dislocation densities are 1.3 ± 0.6 × 10 6 and 8.9 ± 1.7 × 10 6 cm −2 on InP and GaAs, respectively. The devices generate open‐circuit voltages of 0.386 and 0.383 V, respectively, under irradiance producing a short‐circuit current density of ≈10 A cm −2 , yielding bandgap‐voltage offsets of 0.20 and 0.21 V. Power and broadband reflectance measurements are used to estimate thermophotovoltaic (TPV) efficiency. The InP‐based cell is estimated to yield 1.09 W cm −2 at 1100 °C versus 0.92 W cm −2 for the GaAs‐based cell, with efficiencies of 16.8 versus 9.2%. The efficiencies of both devices are limited by sub‐bandgap absorption, with power weighted sub‐bandgap reflectances of 81% and 58%, respectively, the majority of which is assumed to occur in the graded buffers. The 1100 °C TPV efficiencies are estimated to increase to 24.0% and 20.7% in structures with the graded buffer removed, if previously demonstrated reflectance is achieved. These devices also have application to laser power conversion in the 2.0–2.3 µm atmospheric window. Peak laser power converter efficiencies of 36.8% and 32.5% are estimated under 2.0 µm irradiances of 1.86 and 2.81 W cm −2 , respectively.

14 SOLAR ENERGY↗
DOE OSTI2026

Advances in Colloidal InP-Based Quantum Dots for Photocatalytic Hydrogen Evolution

Photocatalytic materials for hydrogen generation are typically categorized into UV-absorbing metal oxides and visible-range semiconductors such as chalcogenides or perovskites, which often incorporate toxic elements. To address environmental concerns of the latter group, indium phosphide (InP)-based quantum dots (QDs) have recently emerged as a less toxic alternative. These nanocrystals (NCs) benefit from a broadband and tunable absorption spectrum, which is well matched for solar photochemistry, and offer suitable electronic characteristics to drive photoinduced charge separation. This perspective provides a comprehensive summary of the recent advancements in developing InP-based NCs with a focus on photocatalytic hydrogen production. We discuss synthetic strategies that enhance the catalytic activity of these materials and highlight key challenges that must be addressed to enhance their performance. Finally, we explore future research directions aimed at improving photocatalytic efficiency and integrating InP-based QDs into practical solar-to-fuel conversion systems.

Hydrogen↗
DOE OSTI2023

Heteroepitaxial chemistry of zinc chalcogenides on InP nanocrystals for defect-free interfaces with atomic uniformity

Heteroepitaxy on colloidal semiconductor nanocrystals is an essential strategy for manipulating their optoelectronic functionalities. However, their practical synthesis typically leads to scattered and unexpected outcomes due to the intervention of multiple reaction pathways associated with complicated side products of reactants. Here, the heteroepitaxy mechanism of zinc chalcogenide initiated on indium phosphide (InP) colloidal nanocrystals is elucidated using the precursors, zinc carboxylate and trialkylphosphine selenide. The high magnetic receptivity of 77 Se and the characteristic longitudinal optical phonon mode of ZnSe allowed for monitoring the sequence of epilayer formation at the molecular level. The investigation revealed the sterically hindered acyloxytrialkylphosphonium and diacyloxytrialkylphosphorane to be main intermediates in the surface reaction, which retards the metal ion adsorption by a large steric hindrance. The transformation of adsorbates to the crystalline epilayer was disturbed by surface oxides. Raman scattering disclosed the pathway of secondary surface oxidation triggered by carboxylate ligands migrated from zinc carboxylate. The surface-initiated heteroepitaxy protocol is proposed to fabricate core/shell heterostructured nanocrystals with atomic-scale uniformity of epilayers. Despite the large lattice mismatch of ZnS to InP, we realised a uniform and interface defect-free ZnS epilayer (~0.3 nm thickness) on InP nanocrystals, as evidenced by a high photoluminescence quantum yield of 97.3%.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2025

Alternate InP synthesis with aminophosphines: solution–liquid–solid nanowire growth

Indium phosphide nanowires are important components in high-speed electronics and optoelectronics, including photodetectors and photovoltaics. However, most syntheses either use high-temperature and costly vapor-phase methodology or highly toxic and pyrophoric tris(trimethylsilyl)phosphine. To expand on the success of the aminophosphine-based InP colloidal quantum dot synthesis, we developed a synthesis for thin (~11 nm) zinc blende InP nanowires at 180 °C using indium tris(trifluoroacetate) and tris(diethylamino)phosphine. A flat nanoribbon morphology was identified by transmission electron and atomic force microscopy analysis, with the stoichiometric (110) lattice plane exposed. Nanowire growth proceeded through a solution–liquid–solid mechanism from in situ-formed indium metal nanoparticles. Molecular byproducts of tris(oleylamino)phosphine oxide and N-oleyltrifluoroacetamide observed by 31 P and 19 F NMR spectroscopy inform a proposed mechanism of indium reduction by the aminophosphine. Morphological control over the nanowire product was achieved by varying the phosphorus injection to control the aspect ratio, the In : P ratio to toggle between nanowires and multipods, and the pre-hot injection evacuation step to favor a quantum dot product. Furthermore, replacing the indium precursor with indium tris(trifluoromethanesulfonate) was found to make bulk zinc blende InP nanowires with an average diameter of >250 nm and tens of microns in length.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2026

Programmable Phase Selection between Altermagnetic and Noncentrosymmetric Polymorphs of MnTe on InP via Molecular Beam Epitaxy

Phase selecting nearly degenerate crystalline polymorphs during epitaxial growth can be challenging yet critical to targeting physical properties for specific applications. Here, we establish how phase selectivity of altermagnetic and noncentrosymmetric polymorphs of MnTe can be programmed by subtle changes to the surface of lattice-matched InP substrates in molecular beam epitaxy growth. Bulk altermagnetic MnTe is thermodynamically stable in the hexagonal NiAs-structure and is synthesized here on the polar (111)A surface (In-terminated) of InP, while the noncentrosymmetric, cubic ZnS-structure with wide band gap (>3 eV), which epitaxially matches III–V materials, is stabilized on the (111)B surface (P-terminated). Electron microscopy, X-ray photoemission spectroscopy, and reflection high-energy electron diffraction indicate that phase selection is triggered at the interface and proceeds along the growing surface. First-principles calculations suggest that interfacial termination and strain have a significant effect on the interfacial energy; stabilizing the NiAs polymorph on the In-terminated surface and the ZnS structure on the P-terminated surface. Here, selectively grown, high-quality, phase pure films of both MnTe polymorphs will enable our understanding of the novel properties of these materials, thereby facilitating their use in new applications ranging from spintronics to microelectronic devices.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Templated Liquid-Phase Epitaxy of InP Structures on Si

We demonstrate direct and over-dielectric heteroepitaxial growth of InP on Si substrates through templated liquid-phase epitaxy. Large grains (5 um) are indicated by electron channeling contrast imaging and epitaxy is confirmed by x-ray diffraction.We demonstrate direct and over-dielectric heteroepitaxial growth of InP on Si substrates through templated liquid-phase epitaxy. Large grains (5 um) are indicated by electron channeling contrast imaging and epitaxy is confirmed by x-ray diffraction.

CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SU↗
DOE OSTI2020

Materials Data on InP by Materials Project

InP is Zincblende, Sphalerite structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. In3+ is bonded to four equivalent P3- atoms to form corner-sharing InP4 tetrahedra. All In–P bond lengths are 2.58 Å. P3- is bonded to four equivalent In3+ atoms to form corner-sharing PIn4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on InP by Materials Project

InP is Halite, Rock Salt structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. In3+ is bonded to six equivalent P3- atoms to form a mixture of edge and corner-sharing InP6 octahedra. The corner-sharing octahedral tilt angles are 0°. All In–P bond lengths are 2.77 Å. P3- is bonded to six equivalent In3+ atoms to form a mixture of edge and corner-sharing PIn6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba2(InP)5 by Materials Project

Ba2(InP)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 P3- atoms to form distorted BaP7 pentagonal bipyramids that share a cornercorner with one InP4 tetrahedra, edges with two equivalent BaP7 pentagonal bipyramids, edges with two equivalent InP4 tetrahedra, and faces with two equivalent BaP7 pentagonal bipyramids. There are a spread of Ba–P bond distances ranging from 3.27–3.33 Å. In the second Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to seven P3- atoms. There are a spread of Ba–P bond distances ranging from 3.30–3.56 Å. There are five inequivalent In+2.20+ sites. In the first In+2.20+ site, In+2.20+ is bonded in a trigonal non-coplanar geometry to three P3- atoms. There are two shorter (2.64 Å) and one longer (2.66 Å) In–P bond lengths. In the second In+2.20+ site, In+2.20+ is bonded in a trigonal non-coplanar geometry to three P3- atoms. There are one shorter (2.63 Å) and two longer (2.65 Å) In–P bond lengths. In the third In+2.20+ site, In+2.20+ is bonded to four P3- atoms to form InP4 tetrahedra that share a cornercorner with one BaP7 pentagonal bipyramid, corners with two equivalent InP4 tetrahedra, and edges with two equivalent BaP7 pentagonal bipyramids. There are a spread of In–P bond distances ranging from 2.63–2.66 Å. In the fourth In+2.20+ site, In+2.20+ is bonded in a trigonal non-coplanar geometry to three P3- atoms. There are two shorter (2.66 Å) and one longer (2.74 Å) In–P bond lengths. In the fifth In+2.20+ site, In+2.20+ is bonded in a trigonal non-coplanar geometry to three P3- atoms. There are two shorter (2.62 Å) and one longer (2.69 Å) In–P bond lengths. There are five inequivalent P3- sites. In the first P3- site, P3- is bonded to three equivalent Ba2+ and three In+2.20+ atoms to form a mixture of edge, corner, and face-sharing PBa3In3 octahedra. The corner-sharing octahedra tilt angles range from 15–68°. In the second P3- site, P3- is bonded to three Ba2+ and three In+2.20+ atoms to form a mixture of edge, corner, and face-sharing PBa3In3 octahedra. The corner-sharing octahedra tilt angles range from 15–61°. In the third P3- site, P3- is bonded to two equivalent Ba2+ and four In+2.20+ atoms to form a mixture of edge and corner-sharing PBa2In4 octahedra. The corner-sharing octahedra tilt angles range from 25–68°. In the fourth P3- site, P3- is bonded to three Ba2+ and three In+2.20+ atoms to form a mixture of distorted edge, corner, and face-sharing PBa3In3 octahedra. The corner-sharing octahedra tilt angles range from 36–65°. In the fifth P3- site, P3- is bonded to three equivalent Ba2+ and three In+2.20+ atoms to form PBa3In3 octahedra that share corners with six PBa3In3 octahedra and edges with nine PBa2In4 octahedra. The corner-sharing octahedra tilt angles range from 25–55°.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Study of an Integration Platform Based on an Adiabatic Active-Layer Waveguide Connection for InP Photonic Device Integration Mirroring That of Heterogeneous Integration on Silicon

In this work, a photonic device integration platform capable of integration of active-passive InP-based photonic devices without the use of material regrowth is introduced. The platform makes use of an adiabatic active-layer waveguide connection (ALWC) to move an optical beam between active and passive devices. The performance of this platform is analyzed using an example made up of four main sections: (1) a fiber coupling section for enabling vertical beam coupling from optical fiber into the photonic chip using a mode-matched surface grating with apodized duty cycles; (2) a transparent waveguide section for realizing passive photonic devices; (3) an adiabatic mode connection structure for moving the optical beam between passive and active device sections; and (4) an active device section for realizing active photonic devices. It is shown that the coupled surface grating, when added with a bottom gold reflector, can achieve a high chip-to-fiber coupling efficiency (CE) of 88.3% at 1550 nm. The adiabatic active-layer mode connection structure has an optical loss of lower than 1% (CE > 99%). The active device section can achieve an optical gain of 20 dB/mm with the use of only 3 quantum wells. The optimized structural parameters of the entire waveguide module are analyzed and discussed.

42 ENGINEERING↗
DOE OSTI2026

Tracking Optical Phonon Dynamics in InP Nanocrystals via Transient Absorption and Femtosecond Stimulated Raman Spectroscopy

Semiconductor nanocrystals (NCs) offer actualized and prospective utility in optoelectronic technologies, yet key aspects of their thermal and vibrational behaviors remain unresolved. Compared with bulk crystals, heat dissipation involving NCs can differ substantially owing to pervasiveness of interfacial scattering, phonon confinement, and relaxed phonon momentum selection rules, as well as influences of ligands. Here, in addition to transient absorption, we use femtosecond stimulated Raman spectroscopy to track nonequilibrium optical-phonon dynamics in InP NCs capped with myristic acid ligands and compare the same particles coated with a ZnS shell. We identify distinct phonon decay pathways in ligand-capped versus ZnS-shelled NCs. Increasing the excitation density and introducing the ZnS shell measurably modify optical-phonon lifetimes, whereas phonon formation times remain largely unchanged. In addition, we observe phonon mode softening in ligand-capped nanocrystals, consistent with lattice expansion. Together, these results demonstrate that core–shell structures can strongly govern nanocrystal thermal dissipation pathways and should be considered a key design parameter for optoelectronic operation.

dissipation↗
DOE OSTI2024

Optimizing the quality factor of InP nanobeam cavities using atomic layer deposition

Photonic crystal nanobeam cavities are valued for their small mode volume, CMOS compatibility, and high coupling efficiency-crucial features for various low-power photonic applications and quantum information processing. However, despite their potential, nanobeam cavities often suffer from low quality factors due to fabrication imperfections that create surface states and optical absorption. In this work, we demonstrate InP nanobeam cavities with up to 140% higher quality factors by applying a coating of Al 2 O 3 via atomic layer deposition to terminate dangling bonds and reduce surface absorption. Additionally, changing the deposition thickness allows precise tuning of the cavity mode wavelength without compromising the quality factor. This Al 2 O 3 atomic layer deposition approach holds great promise for optimizing nanobeam cavities that are well-suited for integration with a wide range of photonic applications.

42 ENGINEERING↗
DOE OSTI2020

Probing the local electronic structure of isovalent Bi atoms in InP

Cross-sectional scanning tunneling microscopy (X-STM) is used to experimentally study the influence of isovalent Bi atoms on the electronic structure of InP. In this work, we map the spatial pattern of the Bi impurity state, which originates from Bi atoms down to the sixth layer below the surface, in topographic, filled-state X-STM images on the natural {110} cleavage planes. The Bi impurity state has a highly anisotropic bowtielike structure and extends over several lattice sites. These Bi-induced charge redistributions extend along the $\langle$110$\rangle$ directions, which define the bowtielike structures we observe. Local tight-binding calculations reproduce the experimentally observed spatial structure of the Bi impurity state. In addition, the influence of the Bi atoms on the electronic structure is investigated in scanning tunneling spectroscopy measurements. These measurements show that Bi induces a resonant state in the valence band, which shifts the band edge toward higher energies. Furthermore, we show that the energetic position of the Bi-induced resonance and its influence on the onset of the valence band edge depend crucially on the position of the Bi atoms relative to the cleavage plane.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2022

Clean quantum point contacts in an InAs quantum well grown on a lattice-mismatched InP substrate

Strong spin-orbit coupling, the resulting large g factor, and small effective mass make InAs an attractive material platform for inducing topological superconductivity. The surface Fermi level pinning in the conduction band enables highly transparent ohmic contact without excessive doping. In this study, we investigate electrostatically defined quantum point contacts (QPCs) in a deep-well InAs two-dimensional electron gas. Despite the 3.3% lattice mismatch between the InAs quantum well and the InP substrate, we report clean QPCs with up to eight pronounced quantized conductance plateaus at zero magnetic field. Source-drain dc bias spectroscopy reveals a harmonic confinement potential with a nearly 5 meV subband spacing. We find a many-body exchange interaction enhancement for the out-of-plane g factor |$g^{*}_{⊥}$|=27±1 , whereas the in-plane g factor is isotropic |$g^{*}_{x}$|=|$g^{*}_{y}$|=12±2 , close to the bulk value for InAs.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

Supercontinuum generation in oxide and semiconductor materials (InP, Si, GaN, GaAs, PbMoO 4 , YVO 4 , ZGP, TiO 2 , diamond) pumped by radiation of the Cr:ZnS fs-MOPA system

Ultrashort light sources in the middle-infrared range are highly beneficial for applications such as gas molecular spectroscopy, remote sensing, atmospheric science, medical treatments, and light–matter interaction studies. Ultrafast lasers utilizing chromium-doped ZnS/Se (Cr:ZnS/Se) have proven to be robust and stable solutions within this spectral region. Nonlinear spectral broadening is fundamentally important, as it pushes the pulse duration limits imposed by the bandwidth of laser media. In this study, we demonstrate the spectral broadening and supercontinuum generation in several bulk materials, including InP, Si, GaN, GaAs, PbMoO 4 , YVO 4 , diamond, and TiO 2 , using pump radiation with up to 4 W average power centered at 2.35 µm from a Cr:ZnS femtosecond MOPA system. Some of the investigated materials have excellent potential as effective media for middle-infrared supercontinuum generation, demonstrating the feasibility of developing a single-cycle pulse middle-infrared laser system.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗