We have investigated the properties of In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.51</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.49</sub> N/GaN disk-in-nanowire light emitting diodes (LEDs) epitaxially grown on silicon substrates by plasma-assisted molecular beam epitaxy. The radiative efficiency nanowire ensemble, obtained from temperature-dependent photoluminescence measurements, under optimized growth conditions is 43%,...

Light sources and photodetectors operating in the far- to midinfrared (FIR/MIR) band (8--12 \textmu{}m, 0.15--0.1 eV) remain relatively poorly developed compared their counterparts visible near-infrared ranges, despite extensive application potential for thermal imaging, standoff sensing, other technologies. This is attributable part lack of narrow-gap materials (0.1 with high optical gain absorption. In this work, a semiconductor, ${\mathrm{Pb}}_{0.7}{\mathrm{Sn}}_{0.3}\mathrm{Se}$,...

We demonstrate the ability to tailor self-assembled growth of In0.5Ga0.5As quantum dots (QDs) on GaSb(111)A surfaces by molecular beam epitaxy. Spontaneous formation via Volmer-Weber mode produces QDs with excellent structural and optical quality. By harnessing tensile strain reduce their band gap energy, these are characterized light emission that extends into midwave infrared wavelength range 3.2-3.9 μm (0.318-0.388 eV). As we increase QD size, can tune alignment from type-III type-II,...

We have examined the responses of GaAs, InP, InAs, and AlAs to 30 keV focused ion beam (FIB) irradiation applied a unified model that consistently explains observed effects. Nanodots were form on InAs under at normal incidence, while nanodots are not AlAs. The FIB response nanodot formation behavior each material is discussed with regard few basic properties for creation growth by action preferential sputtering Ostwald ripening. predicts development stable average size increasing dose,...

Driven by tensile strain, GaAs quantum dots (QDs) self-assemble on In0.52Al0.48As(111)A surfaces lattice-matched to InP substrates. In this study, we show that the tensile-strained self-assembly process for these GaAs(111)A QDs unexpectedly deviates from well-known Stranski-Krastanov (SK) growth mode. Traditionally, formed via SK mode form top of a flat wetting layer (WL) whose thickness is fixed. The inability tune WL has inhibited researchers' attempts fully control QD-WL interactions in...

We investigate the surface morphologies of two series homoepitaxial GaSb(100) thin films grown on substrates by molecular beam epitaxy in a Veeco GENxplor system. The first was at temperatures ranging from 290 to 490°C and serves as control. second using same growth parameters with bismuth used surfactant during growth. compared examine impacts over range GaSb atomic force microscopy film properties Raman spectroscopy scanning electron microscopy. High-resolution x-ray diffraction performed...

Variable‐angle spectroscopic ellipsometry is used to determine the room temperature complex refractive index of molecular beam epitaxy grown GaSb 1− x Bi films with ≤ 4.25% over a spectral range 0.47–6.2 eV. By correlating critical points in extinction coefficient k , energies several interband transitions are extracted as functions content. The observed change fundamental bandgap energy ( E 0 −36.5 meV per %Bi) agrees well previously published values; however, samples examined here show...

GaAs1−xBix has been grown by solid-source molecular beam epitaxy using varying substrate rotation rates. Changes in local bismuth saturation were studied the Bi/Ga pressure ratio across wafer. Films on both GaAs and InGaAs buffer layers with indium content to change strain conditions of bismide layer out-of-plane growth rate. All samples demonstrated vertical composition modulations a period ∼ 4 nm that tracked rate per cycle. The thermal stability these was shown behave similarly bulk...

The refractory metal iridium has many applications in high performance optical devices due to its reflectivity into X-ray frequencies, low oxidation rate, and melting point. Depositing Ir via magnetron sputtering produces quality thin films, but the chamber pressure sputter conditions can change film microstructure on nanoscale. Film is commonly examined through microscopy of cross-sections, which both a destructive characterization method time consuming. In this work, we have utilized...

Antenna coupled detectors break the intrinsic tradeoff between signal and noise by "collecting over a large area" "detecting small area". Most antenna in infrared rely on metal resonator structure. However, there are losses associated with metallic structures. We have demonstrated novel long-wave (LWIR) detector that combines dielectric an antimonide-based absorber. The consists of 3D, subwavelength InAsSb absorber embedded resonant, cylindrical made amorphous silicon. This architecture...

Ion beam irradiation has been examined as a method for creating nanoscale semiconductor pillar and cone structures, but the drawback of inaccurate nanostructure placement. We report on templating InAs spikes by focused ion (FIB) both homoepitaxial films heteroepitaxial InP substrates. These 'nanospikes' are created In droplets, formed due to FIB irradiation, act etch masks underlying InAs. By pre-patterning influence droplet movement, nanospike locations may be controlled with limited...

We report on changes in Ge1−xSnx films (0.065 ≤ x 0.144) after short high-temperature anneals. Films were grown by molecular beam epitaxy (001) Ge wafers, rapidly annealed, and characterized x-ray diffraction, Raman spectroscopy, optical microscopy. Sn segregated to the surface a maximum temperature is inversely related content. Lower content showed little no improvement crystal quality below segregation temperatures, while higher partially relaxed demonstrated improved uniformity for...

We demonstrate that when highly lattice-mismatched GaSb layers are grown on GaAs(111)A substrates, the strain can be relieved by a self-assembled array of interfacial misfit (IMF) dislocations. This 2D consists periodically spaced, pure 60° dislocations lie in plane GaSb/GaAs(111)A interface. The efficient relief provided IMF means exhibits good material quality, with threading dislocation densities 2–3 × 108 cm–2 range. Other through-film defects associated twinned GaSb(111) regions have...

Abstract Films of n-GaAs 1-x Bi x films were grown via molecular beam epitaxy using both Si and Te as dopant sources. Electron mobility was characterized by Hall effect measurements a function carrier concentration content for with bismuth fractions = 0.02 0.06. While GaAsBi:Te shows lower majority than GaAsBi:Si at low concentrations, the two become comparable increases. Furthermore, it observed that in presence bi-metallic Bi-Ga droplets on film surface, doped display p-type behavior,...

We have determined a reproducible set of growth conditions for the self-assembly tensile-strained In1−xGaxAs quantum dot (QD) nanostructures on (111)A surfaces. During molecular beam epitaxy, islands form spontaneously InAs(111)A when Ga content x≥50%. analyze structure and composition InGaAs/InAs(111) samples using atomic force microscopy, transmission electron energy loss spectroscopy. demonstrate control over size areal density as function coverage, composition, substrate temperature....

Variable angle spectroscopic ellipsometry was used to determine the optical properties of n- and p-type GaAs over a doping range 4.6&times;10¹⁶ 9.3&times;10¹⁸ cm^-3 spectral 190 nm 30 μm. Increased concentration observed have several distinct effects on samples' properties: band edge broadens shifts higher energy; E₁ (E₁ + Δ₁) absorption peaks blur together; E₂ peak decreases; sub-bandgap, infrared increases....

Iridium (Ir) is a refractory metal commonly seen in industrial applications, but has great potential for optical applications including metasurfaces. Metasurfaces are used to control the properties of an interface via sub-wavelength surface structures. These patterns require sharply defined features create precise phase interactions. For high-temperature environments, most materials insufficient candidates metasurfaces because sharpness structures lost due edge-rounding or oxidation. Ir...

Ion beam irradiation has previously been demonstrated as a method for creating nanowire-like semiconductor nanostructures, but no previous studies have reported on the electrical properties of those structures.In this work we describe creation and in situ transmission electron microscopy characterization nanoscale InAs spike structures both InP substrates fabricated using focused ion erosion method.Those 'nanospikes' are found to possess internal with varying amounts damaged single...

Small band gap thermophotovoltaics can be engineered to match the thermal spectrum of many heat sources. III-V-Bismides offer new combinations at InP lattice constant. Through simulation, we explore homojunction and heterojunction GaAs <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.76</sub> Bi xmlns:xlink="http://www.w3.org/1999/xlink">0.24</sub> devices, with a 0.25eV, tuned for 1350K source. Homojunction simulated Silvaco-Atlas software...