We report the band alignment parameters of GaN/single-layer (SL) MoS2 heterostructure where GaN thin layer is grown by molecular beam epitaxy on CVD deposited SL-MoS2/c-sapphire. confirm that an SL measuring separation and position room temperature micro-Raman E12g A1g modes, absorbance, micro-photoluminescence bandgap studies. This in good agreement with HRTEM cross-sectional analysis. The determination offset at GaN/SL-MoS2 heterojunction carried out high-resolution X-ray photoelectron...

We study the band discontinuity at GaN/single-layer (SL) WSe2 heterointerface. The GaN thin layer is epitaxially grown by molecular beam epitaxy on chemically vapor deposited SL-WSe2/c-sapphire. confirm that was formed as an SL from structural and optical analyses using atomic force microscopy, scanning transmission electron micro-Raman, absorbance, microphotoluminescence spectra. determination of offset parameters GaN/SL-WSe2 heterojunction obtained high-resolution X-ray photoelectron...

Antiferromagnets with non-collinear spin structures display various properties that make them attractive for spintronic devices. Some of the most interesting examples are an anomalous Hall effect despite negligible magnetization and a unusual polarization directions. However, these effects can only be observed when sample is set predominantly into single antiferromagnetic domain state. This achieved compensated structure perturbed displays weak moments due to canting allows external control....

Group III-nitride semiconductor materials especially AlGaN are key-emerging candidates for the advancement of ultraviolet (UV) photonic devices. Numerous nanophotonics approaches using nanostructures (e.g., nanowires, nanorods, and quantum dots/disks) nanofabrication substrate patterning, crystals, nanogratings, surface-plasmons) have been demonstrated to address material growth challenges enhance device efficiencies devices operating at UV wavelengths. Here, we review progress...

Recent interest in two-dimensional materials has resulted ultra-thin devices based on the transfer of transition metal dichalcogenides (TMDs) onto other TMDs or III-nitride materials. In this investigation, we realized p-type monolayer (ML) MoS2, and intrinsic GaN/p-type MoS2 heterojunction by GaN overgrowth ML-MoS2/c-sapphire using plasma-assisted molecular beam epitaxy. A systematic nitrogen plasma (N2*) gallium (Ga) irradiation studies are employed to understand individual effect doping...

Abstract Progress in the design and fabrication of ultraviolet deep-ultraviolet group III–nitride optoelectronic devices, based on aluminum gallium nitride boron their alloys, heterogeneous integration with two-dimensional oxide-based materials is reviewed. We emphasize wide-bandgap compound semiconductors (i.e., (B, Al, Ga)N) as interest, materials, namely graphene, nitride, transition metal dichalcogenides, along oxide, hybrid integrated materials. examine crystallographic properties...

The valence and conduction band offsets (VBO CBO) at the semiconductor heterojunction are crucial parameters to design active region of contemporary electronic optoelectronic devices. In this report, study alignment In0.15Al0.85N/MoS2 lattice matched heterointerface, large area MoS2 single layers chemical vapor deposited on molecular beam epitaxial grown In0.15Al0.85N films vice versa. We grew InAlN having an in-plane parameter closely matching with that MoS2. confirm is a layer from optical...

There have been recent research advances in AlGaN-based self-assembled nanowires (NWs) as building blocks for ultraviolet (UV) optoelectronics grown by plasma-assisted molecular beam epitaxy. We review the basic growth kinetics on various foundry-compatible-metal/silicon-based substrates and epistructure design UV devices. highlight use of diffusion-barrier-metal thin film silicon substrate a solution to enhance device performance. NWs offer opportunity mitigate detrimental quantum-confined...

Group-III nitride nano-dimensional materials with noncentrosymmetric crystal structure offer an exciting area of piezotronics for energy conversion applications. We experimentally report the piezotronic and piezo-phototronic effects n-InGaN nanowires (NWs) having emission wavelength in visible region (≈510 nm). The n-type InGaN NWs, exhibiting high structural optical quality, were grown by plasma-assisted molecular beam epitaxy (PAMBE) on Ti/TaN/Si substrates to facilitate direct bottom...

We study the surface charge accumulation on InN thin films that strongly effects mobility of carriers. The are formed by MBE in temperature range (400–470 °C) yielding with different morphology, crystallinity, and optical properties. band-gap values determined absorption PL studies found to depend Hall carrier concentration as per Moss-Burstein relation. magnitude near band bending is measured knowing bulk Fermi level position respect valence maximum using X-ray photoelectron spectroscopy...

We study the impact of quantum-confined stark effect (QCSE) on bias dependent micro-photoluminescence emission quantum disk (Q-disk) based nanowires light emitting diodes (NWs-LED) exhibiting amber colored emission. The NWs are found to be nitrogen polar (N-polar) verified using KOH wet chemical etching and valence band spectrum analysis high-resolution X-ray photoelectron spectroscopy. crystal structure quality were investigated by high-angle annular dark field - scanning transmission...

We report the molecular beam epitaxy growth of device quality InN films on GaN epilayer and nano-wall network (NWN) templates deposited c-sapphire by varying film thickness up to 1 μm. The careful experiments are directed towards obtaining high mobility layers having a low band gap with improved crystal quality. dislocation density is quantified using resolution X-ray diffraction rocking curve broadening values symmetric asymmetric reflections, respectively. observe that grown NWN less than...

The dislocation free InxAl1-xN nanowires (NWs) are grown on Si(111) by nitrogen plasma assisted molecular beam epitaxy in the temperature regime of 490 °C–610 °C yielding In composition ranges over 0.50 ≤ x 0.17. We study optical properties these NWs spectroscopic ellipsometry (SE), photoluminescence, and Raman spectroscopies since they possesses minimal strain with reduced defects comparative to planar films. bandgap measurements demonstrated SE where absorption edges NW samples evaluated...

The performance and efficiency of AlGaN ultraviolet light-emitting diodes have been limited by the extremely low light-extraction (LEE) due to intrinsic material properties AlGaN. Here, enhance LEE device, we demonstrate an nanowire diode (NW-LED) integrated with nitride/air distributed Bragg reflector (DBR) nanogratings. Compared a control device (only mesa), NW-LED DBR nanogratings exhibits enhancement in light output power external quantum (EQE) factor ∼1.67. higher EQE are attributed...

We report an unusual thermal quenching of the micro-photoluminescence (µ-PL) intensity for a sandwiched single-layer (SL) MoS 2 .For this study, layers were chemical vapor deposited on molecular beam epitaxial grown In 0.15 Al 0.85 N lattice matched templates.Later, to accomplish air-stable SL-MoS , thin cap layer was /In heterostructure.We confirm that is single from optical and structural analyses using µ-Raman spectroscopy scanning transmission electron microscopy, respectively.By...

A kinetically controlled two-step growth process for the formation of an array dislocation free high mobility InN nanorods (NRs) on GaN nanowall network (NWN) by Molecular Beam Epitaxy is demonstrated here. The epitaxial NWN formed c-sapphire under nitrogen rich conditions, and then changing source from Ga to In at appropriate substrate temperature yields nucleation a self assembled spontaneous m-plane side faceted-InN NR. By HRTEM, NRs are shown be dislocation-free have low band gap value...

A distributed Bragg reflector (DBR) composed of Y <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> -doped HfO (YDH)/SiO layers with high reflectivity spectrum centered at a wavelength ~240 nm is fabricated using radio-frequency magnetron sputtering. Before the DBR deposition, optical properties for single layer YDH, SiO , and thin films were studied spectroscopic ellipsometry...

Abstract Recently a large variety of non‐collinear spin textures have been revealed in various crystals with different symmetry groups. Of particular interest are D 2d that exhibit complex stable and metastable includes antiskyrmions, elliptical Bloch‐skyrmions, fractional‐antiskyrmions, fractional type‐II trivial‐bubbles. The observation these structures necessitates their stabilization via magnetic field temperature protocols which demands thorough understanding creation, transformation,...

We address the carrier concentration, strain, and bandgap issue of InN films grown on c-sapphire at different N-flux by molecular beam epitaxy using x-ray diffraction photoelectron spectroscopy. demonstrate that strain in arises due to point defects like nitrogen interstitials antisites. report minimal biaxial relaxed growth morphology a hydrostatic arising interstitial atoms being partially compensated find variation absorption edge can be attributed defect induced concentration antisites...

Self-assembled nanowires are posed to be viable alternatives conventional planar structures, including the nitride epitaxy for optoelectronic, electronic and nano-energy applications.In many cases, current injection extraction at nanoscopic scale essential marked improvement macroscopic scale.In this investigation, we study mechanism of nanoscale origin flow charged carriers group-III semiconductor surface metal-semiconductor interfaces.Conductive atomic force microscopy (c-AFM) Kelvin probe...

The issue of variable bandgap values for InN films grown on c-sapphire has been addressed in this work. α-InN have deposited nitrogen rich condition at different substrate temperatures bare Al2O3 (0001) by plasma assisted molecular beam epitaxy (PA-MBE). results several complementary characterization techniques show that single crystalline wurtzite is formed, but their orientation depends the temperature. measured these samples (1.78 eV) explained Moss-Burstein shift degenerately n-doped...

The diode junction temperature (Tj) of light emitting devices is a key parameter affecting the efficiency, output power, and reliability. Herein, we present experimental measurements Tj on ultraviolet (UV) AlGaN nanowire (NW) diodes (LEDs), grown thin metal-film silicon substrate using forward voltage electroluminescence peak-shift methods. forward-voltage vs curves show coefficient dVF/dT values −6.3 mV/°C −5.2 mV/°C, respectively. significantly smaller ∼61 °C measured for sample metal...

The issue of ambiguous values the band gap (0.6 to 2 eV) InN thin film in literature has been addressed by a careful experiment. We have grown wurtzite films PA-MBE simultaneously on differently modified c-plane sapphire substrates and characterized complementary structural chemical probes. Our studies discount Mie resonances caused metallic In segregation at grain boundaries as reason for low (≈ 0.6 also formation Indium oxides oxynitrides cause high value 2.0 eV). It is observed that...

We address the issue of obtaining high quality green emitting InGaN nanorods without any phase separation. Role pre-nitridation Si(111) substrate and growth, temperature on morphology, structural optical properties InxGa1−xN films grown by plasma assisted molecular beam epitaxy, has been studied. The nitrogen rich growth environment surface nitridation results in formation vertically well-aligned single crystalline that are coalesced isolated at 400 °C 500 °C, respectively. In incorporation...

In this work, we demonstrated the direct growth of GaN nanowires on indium tin oxide (ITO)-coated fused silica substrate. The were grown catalyst-free using plasma-assisted molecular beam epitaxy (PA-MBE). effect condition morphology and quality is systematically investigated. Structural characterization indicates that grow in (0001) direction directly top ITO layer perpendicular to substrate plane. Optical shows yellow luminescence absent from nanowire's photoluminescence response,...