Thin-film transistors (TFTs) made of transparent channel semiconductors such as ZnO are great technological importance because their insensitivity to visible light makes device structures simple. In fact, there have been several demonstrations TFTs achieving reasonably good field effect mobilities 1–10 cm2/V s, but the overall performance has not satisfactory, probably due presence dense grain boundaries. We modeled boundaries in and performed simulation a TFT by using two-dimensional...

InGaN-based light-emitting diodes (LEDs) have been widely accepted as highly efficient light sources capable of replacing incandescent bulbs. However, applications InGaN LEDs are limited to small devices because their fabrication process involves expensive epitaxial growth by metalorganic vapor phase epitaxy on single-crystal wafers. If we can utilize a low-cost process, such sputtering large-area substrates, fabricate displays. Here, report the GaN (0001) and films amorphous SiO2 pulsed...

In this study, we investigated the basic electrical properties of Si-doped wurtzite GaN films prepared using a low-temperature pulsed sputtering deposition (PSD) process. We found that electron concentration can be controlled in range between 1.5 × 1016 and 2.0 1020 cm−3. For lightly ([Si] = 2.1 cm−3), room temperature (RT) mobility was as high 1008 cm2 V−1 s−1, which dominantly limited by polar optical phonon scattering. Moreover, heavily PSD exhibited an RT 110 s−1 at 2 cm−3, indicated...

We have grown Mg-doped GaN films with low residual hydrogen concentration using a low-temperature pulsed sputtering deposition (PSD) process. The growth system is inherently hydrogen-free, allowing us to obtain high-purity concentrations below 5 × 1016 cm−3, which the detection limit of secondary ion mass spectroscopy. In Mg profile, no memory effect or serious dopant diffusion was detected. as-deposited showed clear p-type conductivity at room temperature (RT) without thermal activation....

Combinatorial laser molecular-beam epitaxy method was employed to fabricate epitaxial Zn1−xMnxO thin films in a high throughput fashion. Local structures around Mn were investigated for these c-axis-oriented by fluorescence x-ray absorption fine structure measurements. It shown that substitutionally replaces Zn (x<0.22) films. Well-structured blue and ultraviolet cathodoluminescence peaks corresponding the intra-d-shell transitions of Mn2+ observed, especially smaller x. The...

Understanding phonon transport properties in defect-laden AlN is important for their device applications. Here, we construct a machine-learning potential to describe with accuracy pristine and AlN, following the template of Behler-Parrinello-type neural network potentials (NNPs) but extending them consider multiple charge states defects. The high our NNP predicting second- third-order interatomic force constants demonstrated through calculations bands, three-phonon anharmonic, phonon-isotope...

In this study, the fundamental properties of heavily Ge‐doped AlGaN films prepared via pulsed sputtering deposition (PSD) are investigated. PSD having an Al content below 34% provides a much higher maximum electron concentration than Si‐doped AlGaN. The carrier concentrations 0.34 Ga 0.66 N as high 1.8 × 10 20 cm −3 . For contents up to 47%, transport is mainly dominated by degenerate metallic conduction. However, 0.49 0.51 demonstrates thermally activated conduction with activation energy...

We have grown AlN films on nearly-lattice-matched (Mn,Zn)Fe2O4 (111) substrates by pulsed-laser deposition at room temperature and investigated their structural properties using reflection high-energy electron diffraction (RHEED), grazing incidence angle x-ray reflectivity (GIXR), (GIXD), atomic force microscope. found that grows epitaxially even temperature. In situ RHEED observations shown the room-temperature growth of starts with two-dimensional mode followed a transition to...

The authors have grown high-quality m-plane GaN (11¯00) films on ZnO substrates using pulsed laser deposition. They found that annealing in a box made of ceramic improves the surface morphology and succeeded layer-by-layer growth annealed even at room temperature (RT). X-ray diffraction reveals high crystalline quality grows RT buffer layer 700°C. 300-nm-thick film substrate contains residual strains because lattice mismatches between them are quite small. relationship in-plane out-of-plane...

We have investigated the growth temperature dependence of structural properties GaN deposited on O-polarity ZnO (0001¯) using pulsed laser deposition. found that atomically abrupt GaN∕ZnO heterointerfaces are obtained at temperatures reduced to below 500°C. also grown room (RT) exhibits a Ga polarity while 700°C N polarity. However, it is possible grow Ga-polarity by introduction RT buffer layer. First principles calculations well explain how may be flat surfaces low temperatures.

AlN films have been grown on atomically flat 6H-SiC (0001) C-polarity substrates by pulsed sputtering deposition (PSD) at room temperature (RT). Stepped and terraced structures were clearly observed the surface of RT-grown films, which is indicative two dimensional growth with surfaces. The full-width half-maximum values X-ray rocking curves for 0004 1012 diffractions as low 150 215 arcsec, respectively. reciprocal space mapping has revealed that introduction misfit dislocations in...

P-type doping of GaN by pulsed sputtering deposition (PSD) at a low growth temperature 480 °C and dramatic reduction in the process for InGaN-based light-emitting diodes (LEDs) were achieved. Mg-doped layers grown on semi-insulating exhibited clear p-type conductivity with hole concentration mobility 3.0 × 1017 cm−3 3.1 cm2 V−1 s−1, respectively. GaN/In0.33Ga0.67N/GaN LEDs fabricated showed rectifying characteristics bright electroluminescence emission near 640 nm. These results indicate...

Although the demand for high-speed telecommunications has increased in recent years, performance of transistors fabricated with traditional semiconductors such as silicon, gallium arsenide and nitride have reached their physical limits. Therefore, new materials high carrier velocities should be sought fabrication next-generation, ultra-high-speed transistors. Indium (InN) attracted much attention this purpose because its electron drift velocity under a electric field. Thick InN films been...

We report a systematic investigation of the transport properties highly degenerate electrons in Ge-doped and Si-doped GaN epilayers prepared using pulsed sputtering deposition (PSD) technique. Secondary-ion mass spectrometry Hall-effect measurements revealed that doping efficiency PSD n-type is close to unity at electron concentrations as high 5.1 × 1020 cm−3. A record low resistivity for 0.16 mΩ cm was achieved with an mobility 100 cm2 V−1 s−1 carrier concentration 3.9 explain this...

This article provides an overview of recent development sputtering method for high-quality III-nitride semiconductor materials and devices. Being a mature deposition technique widely employed in industry, offers many advantages such as low cost, relatively simple equipment, non-toxic raw materials, process temperatures, high rates, sharp interfaces, possibility on large-size substrates, including amorphous flexible varieties. review covers two major research directions: (1) ex situ sputtered...

Abstract ScAlN has garnered substantial attention for its robust piezoelectric and ferroelectric properties, holding promise diverse electronic device applications. However, the interplay between structural attributes physical properties remains poorly understood. This study systematically elucidates characteristics of epitaxial films grown on GaN by low-temperature sputtering. Correlations Sc composition, lattice constants, film strains were revealed utilizing high-resolution X-ray...

We have grown GaN on atomically flat ZnO (000-1) substrates at room temperature with pulsed laser deposition (PLD). found that surfaces of a clear step and terrace structure been obtained by annealing in box made ceramic ZnO. also grows epitaxially even the surface. Reflection high energy electron diffraction (RHEED) observations revealed film layer mode from early stage growth. X-ray reflectivity measurements heterointerface between is quite abrupt its roughness less than 0.5 nm.

Quantum dot (QD) systems for InGaAs/GaAs without a wetting layer have been fabricated on GaAs (001) surfaces by new self-organized growth method using droplet epitaxy with highly dense Ga droplets. Droplets of InGa alloy droplets formed supplying 1) Ga, 2) In and 3) molecular beams, sequentially. These successfully prevented the two-dimensional InGaAs during crystallization under As flux supply. plan-view transmission electron microscope image, QDs density 7×10 9 cm -2 are observed. show...

We have grown In0.25Ga0.75N films on nearly lattice-matched ZnO (0001¯) substrates with atomically flat surfaces at low substrate temperatures using pulsed laser deposition. found that InGaN having a stepped and terraced structure its surface grows temperatures. also in the layer-by-layer mode, even room temperature (RT), while maintaining straight steps terraces from first monolayer. This phenomenon exhibits singular contrast to case of RT epitaxy GaN ZnO, where considerable number defects...

GaN films were grown on a multilayer graphene (MLG)/amorphous SiO2 stack by pulsed sputtering deposition and their structural properties investigated. The MLG show high c-axis orientation. In addition, the exhibit coexisting zincblende wurtzite phases, but phase is suppressed insertion of AlN interlayers. polarity control was demonstrated using interlayers with without surface oxidation. These results indicate that proposed technique can yield high-quality Ga-polarity for potential use in...

Highly conductive Ge-doped GaN epitaxial layers were grown by low-temperature pulsed sputtering, and their fundamental structural electrical properties investigated. The room-temperature (RT) electron concentration was increased to 5.1 × 1020 cm−3 the Ge doping, atomically flat stepped terraced surface crystalline quality of maintained. Consequently, RT resistivity reduced 0.20 mΩ·cm, which is comparable that for typical transparent oxides such as indium tin oxide. contact resistance with a...

Abstract This paper reports AlN barrier Al 0.5 Ga N high electron mobility transistors (HEMTs) with heavily Si-doped degenerate GaN contacts prepared by pulsed sputtering deposition. Selectively regrown n-type exhibit typical properties the concentration and of 2.6 × 10 20 cm −3 115 2 V −1 s , respectively, resulting in a record low contact resistance R C 0.43 Ω mm for AlN/Al HEMTs. The HEMTs displayed remarkable DC output characteristic maximum drain current density 250 mA transconductance...

Highly conductive AlGaN alloys hold a great technological potential, wherein the degenerate n-type doping is key in reducing parasitic resistances electronic and opto-electronic devices. Nonetheless, AlxGa1−xN elaborated conventional methods exhibits degraded electron concentration at high Al compositions. Here, we demonstrated growth of (0 < x ≤ 0.81) with record concentrations by using pulsed sputtering deposition (PSD) method. The fabricated samples were investigated...