Large-scale wurtzite GaN nanowires and nanotubes were grown by direct reaction of metal gallium vapor with flowing ammonia in an 850–900 °C horizontal oven. The cylindrical structures as long 500 μm diameters between 26 ∼100 nm. Transmission electron microscopy, scanning x-ray diffraction used to measure the size samples. Preliminary results show that depends on temperature NH3 flow rate. growth mechanism is discussed briefly. simple method presented here demonstrates can be without use a...

Magnesium incorporation during the molecular-beam epitaxy growth of wurtzite GaN is found to invert Ga-polar (0001) face N-polar face. The polarity identified based on two different sets reconstructions seen film prior and after about 1 monolayer Mg exposure. inversion boundary lie plane from transmission electron microscopy images, a structural model presented for inversion. On face, also stabilize in N-rich regime.

The band gap energy of the alloy InAsSb has been studied as a function composition with special emphasis on minimization strain-induced artifacts. films were grown by molecular beam epitaxy GaSb substrates compositionally graded buffer layers that designed to produce strain-free films. compositions precisely determined high-resolution x-ray diffraction. Evidence for weak, long-range, group-V ordering was detected in materials exhibiting residual strain and relaxation. In contrast, unstrained...

The absorption spectra for the antimonide-based type-II superlattices (SLs) detection in long-wave infrared (LWIR) are calculated and compared to measured data SLs bulk materials with same energy gap (HgCdTe InAsSb). We include results metamorphic InAsSbx/InAsSby small periods as well more conventional strain-balanced InAs/Ga(In)Sb InAs/InAsSb on GaSb substrates. strength small-period is similar materials, while an average lattice constant matched have significantly lower absorption. This...

AlGaN samples grown by plasma-assisted molecular-beam epitaxy on sapphire (0001) substrates, with 20%–50% Al content and without the use of indium, show intense room-temperature photoluminescence that is significantly redshifted, 200–400meV, from band edge. This emission characterized a long lifetime (∼375ps) comparable to seen in low defect density (∼108cm−2) GaN. Room-temperature monochromatic cathodoluminescence images at redshifted peak reveal spatially nonuniform similar observed...

Unrelaxed InAs1−xSbx layers with lattice constants up to 2.1% larger than that of GaSb substrates were grown by molecular beam epitaxy on GaInSb and AlGaInSb compositionally graded buffer layers. The topmost section the buffers was unrelaxed but strained. in-plane constant top layer be equal unstrained given X. InAs0.56Sb0.44 demonstrate photoluminescence peak at 9.4 μm 150 K. minority carrier lifetime measured 77 K for InAs0.8Sb0.2 τ = 250 ns.

We demonstrate a robust superconducting proximity effect in InAs0.5Sb0.5 quantum wells grown with epitaxial Al contacts, which has important implications for mesoscopic and topological superconductivity. Unlike more commonly studied InAs InSb semiconductors, bulk supports stronger spin–orbit coupling larger g-factor. However, these potentially desirable properties have not been previously measured heterostructures superconductors, could serve as platform fault-tolerant computing. Through...

Developing alternative material platforms for use in superconductor–semiconductor hybrid structures is desirable due to limitations caused by intrinsic microwave losses present commonly used III/V systems. With the recent reports on tantalum superconducting qubits that show improvements over Nb and Al counterparts, exploring Ta superconductor systems promising. Here, we study growth of semiconducting Ge (001) substrates grown via molecular beam epitaxy. We at a temperature 400 °C, diffuses...

We demonstrate that high‐Al content ( x > 0.6) Al Ga 1− N films grown in the III‐rich regime by plasma‐assisted molecular beam epitaxy at elevated growth temperatures, ≥900 °C, possess strong, red shifted room temperature (RT) photoluminescence (PL) correlated with presence of lateral nanoscale periodic oscillations composition. As increased from 800 to 900 additional peaks PL spectrum appear ≈275–280 nm and ≈250–255 nm, strongly fundamental absorption edge ≈240 nm. This is characterized...

Thick InAsBi layers were grown for photoluminescence (PL) characterization. The As to In overpressure ratio was carefully characterized and adjusted achieve Bi-droplet-free surfaces. A closed loop feedback system used maintain the during a 5-h deposition sequence. Despite high degree of control growth parameters, evidence local phase separation observed in PL spectra.

GaN films are grown by plasma-assisted molecular-beam epitaxy on SiC substrates. The width of the x-ray rocking curve for (101̄2) reflection exhibits a distinct minimum Ga/N flux ratios which only slightly greater than unity. Correlated with this minimum, surface morphology is somewhat rough, hill and valley topography. Based transmission electron micrographs, reduction in attributed to enhanced annihilation edge dislocations due their tendency cluster at topographic valleys.

Surface reconstructions during homoepitaxial growth of GaN (0001) are studied using reflection high-energy electron diffraction and scanning tunneling microscopy. In agreement with previous workers, a distinct transition from rough to smooth morphology is seen as function Ga N ratio growth. However, in contrast some prior reports, no evidence for 2×2 reconstruction observed. Observations have been made four different nitrogen plasma sources, similar results each case. A structure the surface...

Abstract Multiferroic epitaxial Bi‐Fe‐O thin films of different thicknesses (15–500 nm) were grown on SrTiO 3 (001) substrates by pulsed laser deposition under various oxygen partial pressures to investigate the microstructural evolution in system and its effect misfit strain relaxation magnetic properties films. Films at low pressure show canted antiferromagnetic phase α‐Fe 2 O embedded a matrix BiFeO . The ferromagnetic phase, γ‐Fe is found precipitate inside grains. formation these phases...

In order to enhance the permittivity and tunability of dielectric component, a thin film composite consisting radio frequency sputtered SrTiO3 (STO) buffer layer metalorganic solution deposited Mg-doped BaxSr1−xTiO3 (Mg-BST) overgrowth was developed using affordable industry standard processes materials. The effect STO thickness on response heterostructure investigated. Our results demonstrate that heterostructure, evaluated in metal-insulator-metal configuration Pt/STO/Mg-BST/Pt sapphire...

InAs0.6Sb0.4/Al0.75In0.25Sb-based barrier photodetectors were grown metamorphically on compositionally graded Ga1−xInxSb buffer layers and GaSb substrates by molecular beam epitaxy. At the wavelength of 8 μm T = 150 K, devices with 1-μm thick absorbers demonstrated an external quantum efficiency 18% under a bias voltage 0.45 V.

Abstract The electronic properties of unstrained unrelaxed InAs x Sb 1− alloys have been determined in a wide range alloy compositions using IR magnetospectroscopy, magnetotransport and photoluminescence. All studied n-type background doping with electron concentration decreasing the content. composition dependence follows an empirical exponential law compositions. Both bandgap effective mass on exhibit negative bowing reaching lowest values at = 0.63: E g 0.10 eV, m * 0.0082 0 4.2 K....

GaInSb and AlGaInSb compositionally graded buffer layers grown on GaSb by MBE were used to develop unrelaxed InAs_1-XSb_Xepilayers with lattice constants up 2.1 % larger than that of GaSb. The InAsSb layer was grow InAs_0.12Sb_0.88 InSb. structural optical characterization 1-μm thick InAs_1-xSb_x performed together measurements the carrier lifetime.

Metamorphic heterostructures containing bulk InAs1−xSbx layers and AlInAsSb barriers were grown on GaSb substrates. The lattice mismatch (up to 2.1%) between the substrates InAsSb was accommodated by growth of GaInSb linearly graded buffers. 1 μm thick InAsSb0.44 layer with an absorption edge above 9 exhibited in-plane residual strain about 0.08%. structures x = 0.2 0.44 operated as light emitting diodes at 80 K demonstrated output powers 90 μW 8 5 μm, respectively.

We have grown N-rich, dilute Sb GaN1−xSbx alloys by low temperature molecular beam epitaxy. At growth of <100 °C the material loses crystallinity and becomes primarily amorphous with small crystallites 2–5 nm at a composition >4 at. %. Despite different microstructures found for composition, absorption edge shifts continuously from 3.4 eV (GaN) to close 1 samples content >30 less than 5 % show sufficient bandgap reduction (∼2 eV), making them suitable...