We compare InAlAs/GaAs and InGaAs/GaAs strained-layer superlattices (SLSs) as dislocation filter layers for 1.3-μm InAs/GaAs quantum-dot laser structures directly grown on Si substrates. SLSs are found to be more effective than in blocking the propagation of threading dislocations generated at interface between GaAs buffer layer substrate. Room-temperature lasing ~1.27 μm with a threshold current density 194 A/cm(2) output power ~77 mW has been demonstrated broad-area lasers substrates using layers.

Normal incident photodetection at mid infrared spectral region is achieved using the intersublevel transitions from strain-free GaAs quantum dot pairs in Al0.3Ga0.7As matrix. The are fabricated by high temperature droplet epitaxy, through which zero strain obtained lattice matched materials. Photoluminescence, photoluminescence excitation optical spectroscopy, and visible-near-infrared photoconductivity measurement carried out to study electronic structure of photodetector. Due pairs, a...

A high‐performance 1.3 μm InAs/GaAs quantum‐dot laser directly grown on Si substrates has been achieved by using InAlAs/GaAs strained‐layer superlattice serving as dislocation filter layers (DFLs). The Si‐based achieves lasing operation up to 111°C with a threshold current density of 200 A/cm 2 and an output power exceeding 100 mW at room temperature.

High-performance, multispectral, and large-format infrared focal plane arrays are the long-demanded third-generation technique for hyperspectral imaging, spectroscopy, target identification. A promising solution is to monolithically integrate photodetectors on a silicon platform, which offers not only low-cost but high-resolution by taking advantage of well-established Si-based readout integrated circuits. Here, we report first InAs/GaAs quantum dot (QD) substrates molecular beam epitaxy....

Building optoelectronic devices on a Si platform has been the engine behind development of photonics. In particular, integration optical interconnects onto substrates allows fabrication complex circuits, potentially enabling chip-to-chip and system-to-system communications at greatly reduced cost size relative to hybrid solutions. Although significant effort devoted light generation modulation technologies, efficient electrically pumped emitters have yet be demonstrated. contrast, III–V...

We report for the first time on an aluminum nitride/gallium nitride (AlN/GaN) heterostructure as a microscale Hall effect sensor current sensing applications in extreme environments. The AlN/GaN devices demonstrated high signal linearity function of magnetic field across temperature range from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 193...

Abstract The spontaneously formation of epitaxial GaAs quantum-dot pairs was demonstrated on an AlGaAs surface using Ga droplets as a nano-source. dot pair attributed to the anisotropy diffusion during high-temperature droplet epitaxy.

The realization of high efficiency quantum dot intermediate band solar cells is challenging due to the thermally activated charge escaping at temperatures. enhancement in short circuit current largely undermined by voltage loss. In this paper, InAs/GaAs with direct Si doping dots are studied. open improved increasing concentration dots. recovery as large 105 mV measured. This attributed suppressed thermal from coupling supported external and photoluminescence measurements.

Droplet epitaxy is a flexible nanomaterial growth technique and potential method to fabricate advanced electronic optoelectronic devices. Here, we report strain-free GaAs/Al0.33Ga0.67As quantum ring solar cells fabricated by droplet technique. Photoluminescence used study the structure of lattice-matched cells. Post-growth thermal annealing improve optical quality cell as well device efficiency. A power conversion efficiency 1.8% demonstrated from prototype cell. This work opens new...

A hybrid nanostructure is constructed with self-assembled GaSb/GaAs quantum dots (QDs) coupling to an In 0.125 Ga 0 . 875 As/GaAs well (QW) through a 4.5 nm GaAs thin spacer. This dot-well (QDW) structure retains the characteristics of type II band alignment while enabling flexibility in engineering energy levels by independently controlling configuration QDs, QW, and spacer layer. Photoluminescence measurements prove that this has several advantages comparison containing QDs only. These...

We present the fabrication of ordered quantum rings by conversion partially capped dots. Morphological transformation dots to is demonstrated capping self-assembled Quantum have been fabricated on high index surfaces this growth technique. The lateral ordering introduced engineering strain field a multi-layer InGaAs superlattice template. By using surfaces, one-dimensional GaAs (100) surface was observed evolve into two-dimensional aligned ring arrays.

The III-V nanowire quantum dots (NWQDs) monolithically grown on silicon substrates, combining the advantages of both one- and zero-dimensional materials, represent one most promising technologies for integrating advanced photonic a microelectronics platform. However, there are great challenges in fabrication high-quality NWQDs by bottom-up approach, that is, growth vapor-liquid-solid method, because potential contamination caused external metal catalysts various types interfacial defects...

Abstract Herein we investigate a (001)-oriented GaAs 1− x Bi /GaAs structure possessing surface droplets capable of catalysing the formation nanostructures during Bi-rich growth, through vapour-liquid-solid mechanism. Specifically, self-aligned “nanotracks” are found to exist trailing on sample surface. Through cross-sectional high-resolution transmission electron microscopy nanotracks revealed in fact be elevated above by subsurface planar nanowire, initiated mid-way molecular-beam-epitaxy...

In this paper, we have demonstrated the first InAs/InGaAs/GaAs quantum dots-in-a-well (DWELL) photodetector monolithically grown on silicon substrate. We studied both optical and electrical characteristics of DWELL photodetectors. Time-resolved photoluminescence spectra measured from revealed a long carrier lifetime 1.52 ns. A low dark current density 2.03 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> mA/cm...

Abstract We present a comparative study of the strain relaxation GaN/AlN short-period superlattices (SLs) grown on two different III-nitride substrates introducing amounts compensating into films. grow by plasma-assisted molecular beam epitaxy (0001)-oriented SLs GaN buffer deposited GaN(thick)-on-sapphire template and AlN(thin)-on-sapphire template. The ex-situ analysis strain, crack formation, dislocation density, microstructure SL layers has established that mechanism in these structures...

Germanium tin (GeSn) is a tuneable narrow bandgap material, which has shown remarkable promise for the industry of near- and mid-infrared technologies high efficiency photodetectors laser devices.

Ultralow density (∼106/cm2) of twin InAs quantum dot (QD) hybrid structure was grown by a droplet epitaxy technique. The photoluminescence (PL) from ensemble and individual QD structures showed bimodal behavior an energy transfer between the well-separated (∼190 nm) QDs, which supposedly due to special wetting ring that built channel for exciton transfer. This research demonstrates novel approach fabricate lateral pairs as candidate laterally coupled molecule.

Self-assembled quantum dots (SAQDs) grown under biaxial tension could enable novel devices by taking advantage of the strong band gap reduction induced tensile strain. Tensile SAQDs with low optical transition energies find application in technologically important area mid-infrared optoelectronics. In case Ge, can even cause a highly desirable crossover from an indirect- to direct-gap structure. However, inability grow without dislocations has impeded progress these directions. this article,...

Photoluminescence (PL) is investigated as a function of the excitation intensity and temperature for lattice-matched InGaAs/InAlAs quantum well (QW) structures with thicknesses 7 15 nm, respectively. At low temperature, interface fluctuations result in 7-nm QW PL exhibiting blueshift meV, narrowing linewidth (full width at half maximum, FWHM) from 20.3 to 10 clear transition spectral profile laser increasing four orders magnitude. The also has larger FWHM variation than 15-nm increases ~50...

The instability during the growth and processing of epitaxial GeSn layers with high Sn molar fraction compressive strain is still to be fully studied. In this work, relationship among relief, dislocations, outdiffusion in a content ∼9 atom % was studied as function pre-existing misfit/threading dislocation (MD/TD) density annealing time at 300 °C. For epilayer strained Ge-on-Si virtual substrate (Ge-VS), an increase relief by factor ∼2 observed after 2 h annealing, without significant effect...

The authors report 1.3-μm InAs/GaAs quantum-dot (QD) lasers monolithically grown on a Si substrate by optimising the dislocation filter layers (DFLs). InAlAs/GaAs strained layer superlattices (SLSs) have been presented as DFLs in this study. A distinct improvement QDs was observed when using SLSs because of effective filtering threading dislocations. Consequently, laser with threshold current density 194 A/cm2 at room temperature and an operating high 85°C is successfully demonstrated. These...