A5072329875- Semiconductor Quantum Structures and Devices
- Semiconductor Lasers and Optical Devices
- Photonic and Optical Devices
- Advanced Semiconductor Detectors and Materials
- GaN-based semiconductor devices and materials
- Nanowire Synthesis and Applications
- Semiconductor materials and devices
- Quantum Dots Synthesis And Properties
- Semiconductor materials and interfaces
- Photonic Crystals and Applications
- solar cell performance optimization
- Chalcogenide Semiconductor Thin Films
- Spectroscopy and Laser Applications
- Metamaterials and Metasurfaces Applications
- Electronic and Structural Properties of Oxides
- Advanced Antenna and Metasurface Technologies
- Advanced Fiber Laser Technologies
- Physics of Superconductivity and Magnetism
- Thermal Radiation and Cooling Technologies
- Plasmonic and Surface Plasmon Research
- ZnO doping and properties
- Mechanical and Optical Resonators
- Advanced Condensed Matter Physics
- Ga2O3 and related materials
- Radiation Detection and Scintillator Technologies
University of New Mexico
2016-2025
Stanford University
2021
United States Air Force Research Laboratory
2013-2021
The University of Texas at Arlington
2021
University of Pennsylvania
2021
The Ohio State University
2018-2020
Massachusetts Institute of Technology
2020
The University of Western Australia
2020
Sandia National Laboratories
2020
University of Arizona
2011-2018
Light-emitting sources and devices permeate every aspect of our lives are used in lighting, communications, transportation, computing, medicine. Advances multifunctional "smart lighting" would require revolutionary concepts the control emission spectra directionality. Such might be possible with new schemes regimes light–matter interaction paired developments light-emitting materials. Here we show that all-dielectric metasurfaces made from III–V semiconductors embedded emitters have...
We demonstrate the growth of a low dislocation density, relaxed GaSb bulk layer on (001) GaAs substrate. The strain energy generated by 7.78% lattice mismatch is relieved periodic array 90° misfit dislocations. localized at GaSb∕GaAs interface and has period 5.6nm which determined transmission electron microscope images. No threading dislocations are visible. misfits identified as 90°, rather than 60°, using Burger’s circuit analysis, therefore not associated with generation A density planar...
ReRAM has been considered as one of the potential technologies for next-generation nonvolatile memory, given its fast access speed, high reliability, and multi-level capability. Multiple-layered architectures have used several megabit test-chips memory macros [1-3]. This paper presents a MeOx-based 32Gb test chip developed in 24nm technology.
The manuscript reports that the initial strain relaxation of highly mismatched GaSb layers grown on GaAs (001) is governed by two-dimensional (2D), periodic interfacial misfit (IMF) dislocation array growth mode. Under optimized conditions, only pure 90° dislocations are generated along both [110] and [11¯0] directions located at GaSb/GaAs interface, which leads to very low threading density propagated direction. long-range uniformity subsequent 2D IMF demonstrated via transmission electron...
We report on the thermal boundary conductance across structurally-variant GaSb/GaAs interfaces characterized by different dislocations densities, as well variably-rough Al/GaSb interfaces. The structures are epitaxially grown using both interfacial misfit (IMF) and non-IMF techniques. measure from 100 to 450 K with time-domain thermoreflectance. decreases increasing strain dislocation density. develop a model for transport at in which phonon propagation scattering parallels photon...
The authors demonstrate and characterize type-II GaSb quantum dot (QD) formation on GaAs by either Stranski-Krastanov (SK) or interfacial misfit (IMF) growth mode. mode selection is controlled the gallium to antimony (III/V) ratio where a high III/V produces IMF low establishes SK strain-relaxed QDs, QDs remain highly strained. Both ensembles strong room temperature photoluminescence (PL) with emitting at 1180nm 1375nm. Quantized energy levels along spectral blueshift are observed in 77K PL....
Stable single-mode lasing operation from a pair of coupled GaN nanowires is demonstrated through optical pumping. with different lengths were placed side-by-side in contact to form cavity nanoprobe manipulation. Unlike individual nanowire lasers, which operate combined multiple transverse and longitude mode oscillation, nanowire-pair provides selection mechanism the Vernier effect, can strongly enhance free spectrum range between adjacent resonant modes generate stable high side-mode...
We report on the room temperature thermal conductivity of AlAs-GaAs superlattices (SLs), in which we systematically vary period thickness and total between $2--24\phantom{\rule{0.16em}{0ex}}\mathrm{nm}$ $20.1--2,160\phantom{\rule{0.16em}{0ex}}\mathrm{nm}$, respectively. The increases with SL plateaus at a around 200 nm, showing clear transition from quasiballistic to diffusive phonon transport regime. These results demonstrate existence classical size effects SLs, even highest interface...
Since the initial proposal in 1999 by Noda <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> , photonic crystal surface emitting lasers (PCSELs) have shown to achieve large area, coherent lasing with a narrow, single mode beam. Owing their unique orthogonal electrical/optical cavity scheme, PCSELs emerged as one of most promising platforms for high power diode lasers. In this paper, we report performance trade-offs and challenges...
We report on the properties of SrTb2O4, a frustrated zigzag ladder antiferromagnet, studied by single crystal neutron diffraction (with polarised neutrons in zero field and unpolarised an applied magnetic field), as well spectroscopy polycrystalline sample. The scattering results are supported magnetisation heat capacity measurements. In field, data show no transition to magnetically ordered state down lowest experimentally available temperature 35 mK, material remains disordered this...
The thermal stability of GaAsSb/InP is known to be compromised by group-V volatility and intermixing at the heterojunction that adversely impact performance subsequently fabricated optoelectronic or high-speed devices. We interrogate interface trace its degradation during extended annealing, where we observe significant nanostructure formation. Scanning transmission electron microscopy reveals formation pyramidal nanostructures extend from epitaxial layer into substrate. Energy-dispersive...
We describe the growth mechanisms of highly mismatched (Δao∕ao=13%) defect-free AlSb on Si(001) substrates. Nucleation occurs during first few monolayers deposition by crystalline quantum dot formation. With continued growth, islands coalesce into a bulk material with no vertically propagating defects. Strain energy from AlSb∕Si interface is dissipated crystallographic undulations in zinc-blende lattice, as confirmed high-resolution transmission electron microscopy (TEM) images. Reciprocal...
We describe optical and structure characteristics of InAs quantum dashes grown on a GaAs substrate using an AlGaAsSb metamorphic buffer. The buffer increases the lattice constant growth matrix from 5.653 to 5.869 Å. increased yields mismatch with active region only 3.2% accommodates large In content access emission wavelengths &gt;2.0 μm. From our comparison dot structures, we conclude that elongated dash formation is due asymmetric surface bonds in zinc blende crystal control migration...
The authors describe simultaneous interfacial misfit (IMF) array formation along with antiphase domain (APD) suppression in highly mismatched (Δa0/a0=13%) AlSb grown on a 5° miscut Si (001) substrate. Strain energy from the AlSb/Si heterojunction is accommodated by self-assembled two-dimensional of pure 90° dislocations confined to interface. 13% lattice mismatch establishes IMF period ∼3.46 nm. This spacing well matched step length Furthermore, substrate geometry suppresses APD due double...
Ring-shaped $\mathrm{GaSb}/\mathrm{GaAs}$ quantum dots, grown by molecular beam epitaxy, were studied using cross-sectional scanning tunneling microscopy. These rings have an outer shape of a truncated pyramid with baselengths around 15 nm and heights about 2 but are characterized clear central opening extending over 40% the baselength. They form spontaneously during growth subsequent continuous capping dots due to large strain substantial As-for-Sb exchange reactions leading strong Sb segregation.
We report on a type-II InAs/GaSb strained layer superlattice (SLS) photodetector (λ ~4.3 µm at 77 K) with nBn design grown GaAs substrate using interfacial misfit dislocation arrays to minimize threading dislocations in the active region. At K and 0.1 V of applied bias, dark current density was equal 6 × 10−4 A cm−2 maximum specific detectivity D* estimated 1.2 1011 Jones (at 0 V). 293 K, zero-bias found be ~109 which is comparable SLS detector GaSb substrate.
We report structural analysis of completely relaxed GaSb epitaxial layers deposited monolithically on GaAs substrates using interfacial misfit (IMF) array growth mode. Unlike the traditional tetragonal distortion approach, strain due to lattice mismatch is spontaneously relieved at heterointerface in this growth. The complete and instantaneous relief GaSb/GaAs interface achieved by formation a two-dimensional Lomer dislocation network comprising pure-edge (90°) dislocations along both [110]...
We report on a mid-wave infrared (λ50% cut-off ∼5.4 μm at 77 K) Ga-free Type II InAs/InAsxSb1-x (x = 0.65) superlattice detector Radiometric measurements reveal quantum efficiency of 20% (λ = 4 μm, with dark current density 2.1 × 10−4 A/cm2 (−10 mV) spectral response observable up to 210 K. Although the Shockley-Read-Hall lifetime is expected be longer for superlattices, larger than that conventional InAs/GaSb detectors. This attributed increased probability carrier tunneling due reduced...
Anisotropic carrier transport properties of unintentionally doped InAs/InAs0.65Sb0.35 type-II strain-balanced superlattice material are evaluated using temperature- and field-dependent magnetotransport measurements performed in the vertical direction on a substrate-removed metal-semiconductor-metal device structure. To best isolate measured to superlattice, fabrication entails flip-chip bonding backside processing remove substrate deposit contact metal directly bottom an etched mesa....
The effect of majority carrier concentration and minority lifetime on the performance mid-wave infrared ( λ cutoff = 5.5 μ m ) nBn detectors with variably doped InGaAs/InAsSb type-II superlattice absorbers is investigated. detector layer structures are grown by molecular beam epitaxy such that their absorbing layers either undoped, uniformly a target density 4 × 1015 cm−3, or graded profile, variable-area mesa arrays fabricated. Each material's temperature-dependent determined time-resolved...
The authors report the optical characteristics of GaSb∕GaAs self-assembled quantum dots (QDs) embedded in an InGaAs well (QW). Variations In composition QW can significantly alter emission wavelength up to 1.3μm and efficiency. Lasing operation at room temperature is obtained from a 2-mm-long device containing five stacked GaSb QDs In0.13Ga0.87As QWs 1.026μm with threshold current density 860A∕cm2. probable lasing transition involves electrons holes confined QDs, respectively, resulting...
GaSb quantum rings in GaAs were studied by cross-sectional scanning tunneling microscopy. The have an outer shape of a truncated pyramid with typical lateral extensions between 10 and 30nm heights 1 3nm, depending on the molecular beam epitaxy growth conditions. A clear central opening varying diameter more or less conical shape, filled GaAs, is characteristic for rings. self-organized formation during subsequent fast overgrowth dots attributed to combination large strain strong Sb...