A5012050022- Ga2O3 and related materials
- GaN-based semiconductor devices and materials
- Semiconductor materials and devices
- ZnO doping and properties
- Graphene research and applications
- 2D Materials and Applications
- Advanced Photocatalysis Techniques
- Quantum and electron transport phenomena
- Electronic and Structural Properties of Oxides
- Nanowire Synthesis and Applications
- Metal and Thin Film Mechanics
- Quantum Dots Synthesis And Properties
- Acoustic Wave Resonator Technologies
- Integrated Circuits and Semiconductor Failure Analysis
- Molecular Junctions and Nanostructures
- Silicon Carbide Semiconductor Technologies
- Advanced Memory and Neural Computing
- Copper-based nanomaterials and applications
- Advanced Sensor and Energy Harvesting Materials
- Carbon Nanotubes in Composites
- Chalcogenide Semiconductor Thin Films
- Semiconductor Quantum Structures and Devices
University of South Carolina
2019-2024
Texas State University
2018-2020
Universidad San Marcos
2019
Khulna University of Engineering and Technology
2013-2014
Fully inkjet-printed device fabrication is a crucial goal to enable large-area printed electronics. The limited number of two-dimensional (2D) material inks, the bottom-gated structures, and low current on/off ratio thin-film transistors (TFTs) has impeded practical applications 2D TFTs. In search for TFTs with high ratios, we introduce stable efficient method nitrogen-doped graphene (NDG) ink preparation inkjet printing by liquid-phase exfoliation. NDG thin film print-stacked molybdenum...
An in situ metal-organic chemical vapor phase epitaxy is used to grow a complete AlGaN/GaN metal oxide semiconductor heterojunction field effect transistor (MOSHFET) structure, gated by gallium (Ga2O3) layer; we observed reduction the interfacial trap density compared its version wherein Ga2O3 was grown ex situ, after breaking vacuum, all else being same. A remarkable decrease charge for MOSHFET structures range of 70%–88% 10–30 nm layer thickness and improvements other electrical parameters...
We report a comparative spectroscopic study on the thin films of epitaxial aluminum nitride (AlN) basal plane sapphire (Al2O3) substrates grown in hydrogen (H2) and nitrogen (N2) gas reaction environments. AlN similar thicknesses (~3.0 µm) were by metal-organic chemical vapor deposition (MOCVD) for comparison. The impact environment epilayers was characterized using high-resolution X-ray diffraction (HR-XRD), photoelectron spectroscopy (XPS), Raman scattering (RS), secondary ion mass (SIMS),...
We report the growth of zirconium oxide (ZrO<sub>2</sub>) as a high-<italic>k</italic> gate dielectric for an inkjet-printed transistor using low-temperature atomic layer deposition (ALD) from tetrakis(dimethylamido)zirconium (TDMAZr) and water precursors.
We report an Ultrawide Bandgap Al0.4Ga0.6N channel metal-oxide-semiconductor heterostructure field effect transistor with drain currents exceeding 1.33 A mm−1 (pulse) and 1.17 (DC), around a 2-fold increase over past reports. This was achieved by incorporating hybrid barrier layer consisting of AlN spacer, n-doped Al0.6Ga0.4N thin reverse graded AlxGa1–xN (x from 0.60 to 0.30) cap layer. To enhance current spreading, "perforated" layout comprising narrow sections separated blocking islands...
The growth of monoclinic phase‐pure gallium oxide (β‐Ga 2 O 3 ) layers by metal–organic chemical vapor deposition on c‐plane sapphire and aluminum nitride (AlN) templates using silicon‐oxygen bonding (SiO x as a phase stabilizer is reported. β‐Ga are grown triethylgallium, oxygen, silane for gallium, silicon precursors, respectively, at 700 °C, with without flow in the process. samples SiO stabilization show notable change from roughness resistivity, 16.2 to 4.2 nm 85.82 135.64 Ω cm,...
We demonstrate a fast solution phase ligand exchange process to generate AgBiS2 nanocrystal inks using cinnamic acid derivative as an additive accelerate the transfer polar solvents. Photoconductivity in thin films assembled from is achieved by single deposition step, avoiding multiple layer iterations. The remain colloidally stable after several days, and photoconductor devices showcase response times <4 ms, high on/off ratios ∼20, film conductivities of ∼3 × 10–8 S/cm, highlighting promise...
We report the electrical properties of Al0.3Ga0.7N/GaN heterojunction field effect transistor (HFET) structures with a Ga2O3 passivation layer grown by metal–organic chemical vapor deposition (MOCVD). In this study, three different thicknesses β-Ga2O3 dielectric layers were on leading to metal-oxide-semiconductor-HFET or MOSHFET structures. X-ray diffraction (XRD) showed (2¯01) orientation peaks in device structure. The van der Pauw and Hall measurements yield electron density ~ 4 × 1018...
We report on 193 nm excimer laser-based liftoff (LLO) of Al0.26Ga0.74N/GaN high electron mobility transistors (HEMTs) with thick (t &gt; 10 μm) AlN heat spreading buffer layers grown over sapphire substrates. The use the layer resulted in thermal resistance (Rth) 16 K mm/W for as-fabricated devices sapphire, which is lower than value ∼25–50 standard HEMT structures without heat-spreaders. Soldering LLO onto a copper sink led to further reduction Rth 8 mm/W, comparable published...
We report the electrical properties of Al0.3Ga0.7N/GaN heterojunction field effect transistor (HFET) structures with a Ga2O3 passivation layer grown by metal-organic chemical vapor deposition (MOCVD). In this study, three different thicknesses dielectric layers were on leading to metal-oxide-semiconductor-HFET or MOSHFET structures. X-ray diffraction (XRD) showed (&macr;201) orientation peaks -Ga2O3 in device structure. The van der Pauw and Hall measurements yield electron density ~ 4...
Graphene is an excellent material for flexible electronics due to its high carrier transport properties. We report a graphene field effect transistor on polyimide substrate using oxide as top-gate dielectric. Good current saturation and peak hole electron mobilities of 496 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /(V.s) 164 are observed, respectively, the proposed intrinsic RF device. A maximum transconductance 0.42 mS cutoff...
This paper introduces the development of a novel ink, design, fabrication, and characterization all inkjet-printed two-dimensional (2D) materials-based field effect transistor with high current on/off ratio. A stable efficient method inkjet printing is developed for nitrogen-doped graphene (N-graphene) nanosheets. Good area coverage N-graphene percolation clusters observed from SEM image. The Raman spectrum reveals amount disorder in nanoflakes due to nitrogen doping. on-off ratio 336...
We report on the surface properties of aluminum-gallium-oxide [(AlxGa1−x)2O3] thin films grown c-plane sapphire substrates, which form building block heterojunction semiconductor devices, by metal–organic chemical vapor deposition (MOCVD). The (AlxGa1−x)2O3 with aluminum mole fraction (composition) ranging from x = 0 to 0.36 were analyzed using x-ray diffraction (XRD) and atomic force microscopy (AFM). increase in composition resulted shift XRD peaks larger 2θ angles due decrease lattice...
Ultrawide bandgap (UWBG) AlGaN-channel metal-oxide-semiconductor heterostructure field-effect transistors (MOSHFETs) with a ZrO2 gate dielectric achieve peak current in excess of 0.4 A/mm and ON/OFF ratios &gt;106 subthreshold swings as low 110 mV/decade. These devices have strong potential for use power radio frequency electronics or true solar-blind photodetectors. In this work, we present the photoresponse analysis UWBG AlGaN MOSHFETs. Persistent photoconductivity decay time above 10...
We demonstrated a metal-organic chemical vapor deposition (MOCVD) of smooth and thick monoclinic phase-pure gallium oxide (Ga<sub>2</sub>O<sub>3</sub>) on c-plane sapphires using silicon-oxygen bonding (SiO<sub>x</sub>) as phase stabilizer. were able to grow ~580nm β-Ga2O3 sapphire by MOCVD at 700 oC through stabilization silane. The samples grown with silane show reduction in the surface roughness resistivity from 10 nm 5 371 Ω.cm 136 Ω.cm, respectively. X-ray diffraction (XRD) reveals...
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Abstract We report a comparative spectroscopic study on the thin films of epitaxial aluminum nitride (AlN) basal plane sapphire (Al 2 O 3 ) substrates grown in hydrogen (H and nitrogen (N gas reaction environments. AlN similar thicknesses (~ 3.0 µm) were by metal-organic chemical vapor deposition (MOCVD) for comparison. The impact environment epilayers was characterized using high-resolution x-ray diffraction (HR-XRD), photoelectron spectroscopy (XPS), Raman scattering (RS), secondary ion...
Ultra-wide bandgap semiconductors have attracted much interest over the last decade. These materials strong chemical bonding that led to high temperature tolerance, voltage and power handling capabilities as described by Baliga figure of merit. Al-rich III-nitride are expected best performance industry standard Si, newer options such SiC GaN. Continuous improvements dictate miniaturization electronic devices, leading increasingly higher densities in smaller footprints, heating causes system...
A study is performed on extrinsic performance of graphene field effect transistor a flexible polyimide substrate with oxide gate dielectric. Using self-consistent calculation, it shown that quantum capacitance retains nonzero minimum at the dirac point. Excellent electron and hole mobilities maximum current 137 μA are obtained for this device. RF analysis has capable amplifying input signal frequency as high 1.71 GHz. We have demonstrated shows higher leakage than conventional transistor.
We report the gate leakage current and threshold voltage characteristics of Al<sub>0.3</sub>Ga<sub>0.7</sub>N/GaN heterojunction field effect transistor (HFET) with metal-organic chemical vapor deposition (MOCVD) grown β-Ga<sub>2</sub>O<sub>3</sub> as a dielectric for first time. In this study, GaN channel HFET passivated metal-oxide-semiconductor-HFET (MOS-HFET) structures were in MOCVD using N<sub>2</sub> carrier gas on sapphire substrate. X-ray diffraction (XRD) atomic force microscopy...
Abstract Ultrawide bandgap gallium oxide (Ga 2 O 3 ) is a promising material for power semiconductor devices and deep ultraviolet (UV) solar-blind photodetectors. Understanding the properties of point defects in Ga necessary to realize better-performing devices. A comprehensive study based on density functional theory (DFT), using generalized gradient approximation (GGA): Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional, corundum (α), monoclinic (β), orthorhombic (ε) phases...