A5101975971- Ga2O3 and related materials
- ZnO doping and properties
- GaN-based semiconductor devices and materials
- Advanced Photocatalysis Techniques
- Electronic and Structural Properties of Oxides
- Semiconductor materials and devices
- Semiconductor Quantum Structures and Devices
- Photocathodes and Microchannel Plates
- Metal and Thin Film Mechanics
- Advancements in Semiconductor Devices and Circuit Design
- 2D Materials and Applications
- Radio Frequency Integrated Circuit Design
- Conducting polymers and applications
- Graphene research and applications
- Organic Light-Emitting Diodes Research
- Quantum and electron transport phenomena
- X-ray Spectroscopy and Fluorescence Analysis
- Organic Electronics and Photovoltaics
- Thermal properties of materials
- Plasma Diagnostics and Applications
- Quantum, superfluid, helium dynamics
- Lung Cancer Research Studies
- Magnesium Oxide Properties and Applications
- X-ray Diffraction in Crystallography
- Barrier Structure and Function Studies
First Hospital of Jilin University
2025
Jilin University
2025
Tsinghua University
2024
University of California, Santa Barbara
2018-2023
Georgia Institute of Technology
2021
University of California System
2021
The Ohio State University
2008-2020
University of Utah
2020
Pennsylvania State University
2020
Kyma Technologies (United States)
2020
Solid state UV emitters have many advantages over conventional sources. The (Al,In,Ga)N material system is best suited to produce LEDs and laser diodes from 400 nm down 210 nm—due its large tuneable direct band gap, n- p-doping capability up the largest bandgap AlN a growth fabrication technology compatible with current visible InGaN-based LED production. However AlGaN based UV-emitters still suffer numerous challenges compared their counterparts that become most obvious by consideration of...
In this work, we demonstrate a high mobility two-dimensional electron gas (2DEG) formed at the β-(AlxGa1-x)2O3/Ga2O3 interface through modulation doping. Shubnikov-de Haas (SdH) oscillations were observed in modulation-doped structure, indicating high-quality channel heterojunction interface. The formation of 2DEG was further confirmed by weak temperature dependence carrier density, and peak low found to be 2790 cm2/Vs, which is significantly higher than that achieved bulk-doped Beta-phase...
Modulation-doped heterostructures are a key enabler for realizing high mobility and better scaling properties performance transistors. We report the realization of modulation-doped two-dimensional electron gas (2DEG) at beta(Al0.2Ga0.8)2O3/ Ga2O3 heterojunction using silicon delta doping. The formation 2DEG was confirmed capacitance voltage measurements. A channel used to realize field-effect transistor. demonstration modulation doping in beta-(Al0.2Ga0.8)2O3/ material system could enable...
In this work, we report record electron mobility values in unintentionally doped β-Ga2O3 films grown by metal-organic chemical vapor deposition. Using degenerately Sn-doped regrown n+ contact layers, were able to maintain Ohmic the down 40 K, allowing for reliable temperature-dependent Hall measurement. An of 176 cm2/V s and 3481 measured at room temperature 54 respectively. The low mobilities are both among highest reported a bulk film. A net background charge concentration 7.4 × 1015 cm−3...
In this work, we demonstrate modulation-doped β-(AlxGa1-x)2O3/Ga2O3 double heterostructure field effect transistors. The maximum sheet carrier density for a two-dimensional electron gas (2DEG) in is limited by the conduction band offset and parasitic channel formation barrier layer. We to realize β-(AlxGa1-x)2O3/Ga2O3/(AlxGa1-x)2O3 quantum well, where electrons can be transferred from below above β-Ga2O3 well. confined 2DEG charge of 3.85 × 1012 cm−2 was estimated low-temperature Hall...
We report (010)-oriented β-Ga2O3 bevel-field-plated mesa Schottky barrier diodes grown by low-pressure chemical vapor deposition (LPCVD) using a solid Ga precursor and O2 SiCl4 sources. with good ideality low reverse leakage were realized on the epitaxial material. Edge termination beveled field plates yielded breakdown voltage of −190 V, maximum vertical electric fields 4.2 MV/cm in center 5.9 at edge estimated, extrinsic RON 3.9 mΩ·cm2 extracted intrinsic 0.023 mΩ·cm2. The reported results...
We report silicon delta-doped β-Ga <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> metal semiconductor field effect transistors (MESFETs) with source-drain ohmic contacts formed by patterned regrowth of n-type Ga . show that regrown can enable a lateral low-resistance contact to the two-dimensional electron gas channel, resistance lower than 1.5 Ω-mm. The fabricated MESFET has peak...
Threshold voltage instability was observed on β-Ga <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> transistors using double-pulsed current-voltage and constant drain current deep level transient spectroscopy (DLTS) measurements. A total of 0.78 V attributed to two distinct trap levels, at E xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> -0.70 -0.77 eV, which need be mitigated for...
We investigate voltage breakdown of a β-(Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.22</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.78</sub> ) xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /Ga modulation-doped field-effect transistor with gate-connected field-plate and silicon nitride (SiN xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> as the passivation layer....
We report on record low free carrier concentration values in metalorganic chemical vapor deposition (MOCVD) grown β-Ga2O3 by using N2O for oxidation. Contrary to the pure oxygen, oxidant produced thin films co-doped with nitrogen and hydrogen, but incorporation efficiency of both impurities is strongly dependent key MOCVD growth parameters. An array conditions resulted N H concentrations ranging as high ∼2 × 1019 cm−3 ∼7 1018 cm−3, respectively, no SIMS detectable was identified. Films...
We report on record electron mobility values measured in lightly Si doped homoepitaxial β-Ga2O3 grown by metal-organic chemical vapor deposition. The transport properties of the films were studied using temperature-dependent Hall measurements. Numerous (010) layers at different conditions showed peak exceeding 104 cm2/V s low temperature (LT), with highest value 11 704 46 K. room mobilities between 125 and 160 net background charge concentration ∼5 × 1015 cm−3 ∼2 1016 cm−3. obtained LT for...
We report on the high-field transport characteristics and saturation velocity in a modulation-doped β-(Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> ) xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /Ga heterostructure. The formation of 2-D electron gas (2DEG) structure was confirmed from Hall measurements, 2DEG channel...
We report on a high performance Pt/n−Ga2O3/n+Ga2O3 solar blind Schottky photodiode that has been grown by metalorganic chemical vapor deposition. The active area of the was fabricated using ∼30 Å thick semi-transparent Pt up to 90% transparency UV radiation with wavelengths &lt; 260 nm. exhibited characteristics turn-on voltage ∼1 V and rectification ratio ∼108 at ±2 showed deep detection 0 V. good device such as an ideality factor 1.23 breakdown ∼110 spectral response maximum absolute...
Sn doping of (010) β-Ga2O3 grown by conventional plasma-assisted molecular beam epitaxy (PAMBE) and via metal oxide catalyzed (MOCATAXY) using a supplied indium flux during (MBE) growth was investigated. While high concentrations were achievable over range conditions in PAMBE, less than 1019 cm−3 resulted non-uniform profiles for constant cell temperatures, as well run-to-run variation doping. MOCATAXY allowed sharp wide donor from 3.9 × 1016 to 2 maximum room temperature Hall mobility 136...
NaYF4:Yb,Tm@TiO2 core–shell composites were synthesized via a facile hydrothermal method. The highly crystalline TiO2 shell can be uniformly coated onto lanthanide-doped NaYF4 microrods and nanorods under mild conditions without calcination. thickness of the tuned by varying ratio fluoride rods Ti precursors. microcomposite with moderate shows excellent photocatalytic activity near-infrared irradiation.
Ultra-violet emitters have several applications in the areas of sensing, water purification, and data storage. While III-Nitride semiconductor system has band gap region necessary for ultraviolet emission, achieving efficient solid state remains a challenge due to low p-type conductivity high contact resistance wide AlGaN-based ultra-violet light emitters. In this work, we show that interband tunneling can be used non-equilibrium injection holes into Polarization-engineered tunnel junctions...
We report on the small-signal high frequency characteristics of highly scaled graded AlGaN channel polarization-doped field-effect transistors (PolFETs) that show constant current gain cutoff (f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> ) and maximum oscillation xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> profiles as a function density or gate bias. The device design includes upward downward Al composition grading to...
We report on the high efficiency tunnel-injected ultraviolet light emitting diodes (UV LEDs) at 287 nm. Deep UV LED performance has been limited by severe internal absorption in p-type contact layers and low electrical injection due to poor conduction. In this work, a polarization engineered Al0.65Ga0.35N/In0.2Ga0.8N tunnel junction layer is adopted for non-equilibrium hole replace conventionally used direct contact. A reverse-graded AlGaN further introduced realize resistance top n-AlGaN...
The integration of two-dimensional materials such as transition metal dichalcogenides with bulk semiconductors offer interesting opportunities for 2D/3D heterojunction-based novel device structures without any constraints lattice matching. By exploiting the favorable band alignment at GaN/MoS2 heterojunction, an Esaki interband tunnel diode is demonstrated by transferring large area, Nb-doped, p-type MoS2 onto heavily n-doped GaN. A peak current density 446 A/cm2 repeatable room temperature...
In this letter, we demonstrate high-performance vertical solar-blind Schottky photodetectors on MBE-grown homoepitaxial (010)-oriented β-Ga <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> films. The structure, consisting of (100 nm) /(60 n <sup xmlns:xlink="http://www.w3.org/1999/xlink">++</sup> , was grown a Fe-doped insulating (010) substrate. Ni/Au and indium were used as the Ohmic...
We report on the effect of iron (Fe)-doped semi-insulating buffers electron transport and DC-RF dispersion in Si delta (δ)-doped β-Ga2O3 metal-semiconductor field transistors. The distance between 2-dimensional gas Fe-doped region was investigated, Fe doping buffer found to have a significant properties. It that thicker than 600 nm can enable better properties for transistors, while maintaining relatively low parasitic leakage. This work provide guidance use insulating future Ga2O3 based electronics.
We report a systematic investigation on the anisotropic etching behavior of β-Ga2O3. A wagon wheel pattern was designed and fabricated (010)-oriented β-Ga2O3 substrates. The wet in hot phosphoric acid found to be effective reducing sidewall roughness caused by plasma dry etching. angular dependence etch rate inclination angles after evaluated. fins aligned along [001] direction showed nearly vertical sidewalls fast rate, making it feasible for fabrication ultrascaled channel devices. range...
Increased attention has been paid to the thermal management of β-Ga2O3 devices as a result large resistance that can present itself in part due its low intrinsic conductivity. A number die-level approaches exist could be viable for management. However, they have not assessed exclusively. Here, we explore limits various die level schemes on metal–semiconductor field-effect transistor using numerical simulations. The effects cooling device channel temperature were comprehensively investigated,...
We report on tunnel-injected deep ultraviolet light emitting diodes (UV LEDs) configured with a polarization engineered Al0.75Ga0.25 N/In0.2Ga0.8 N tunnel junction structure. Tunnel-injected UV LED structure enables n-type contacts for both bottom and top contact layers. However, achieving Ohmic to wide bandgap n-AlGaN layers is challenging typically requires high temperature metal annealing. In this work, we adopted compositionally graded layer non-alloyed obtained low resistance of ρc =...