Yuanqi Huang

Influence of oxygen vacancies on the photoresponse of β-Ga2O3/SiC n–n type heterojunctions

β-Ga2O3/4H-SiC n–n type heterojunctions have been fabricated by depositing high quality β-Ga2O3 films on c-axis orientation n-type 4H-SiC substrates using laser molecular beam expitaxy. The influences of oxygen vacancies on the junction performances are investigated. It is found that the existence of oxygen vacancies degrades the rectifying and photoresponse properties of the heterojunctions. A large rectification ratio of 1900, a high 254 nm ultraviolet photosensitivity of 6308% and a zero response of 365 nm ultraviolet have been achieved by reducing oxygen vacancies. It is supposed that the oxygen vacancies in Ga2O3 affect the depletion layer of the n–n junction greatly.

Epitaxial growth and characterization of CuGa2O4 films by laser molecular beam epitaxy

Ga2O3 with a wide bandgap of ∼ 4.9 eV can crystalize in five crystalline phases. Among those phases, the most stable monoclinic β-Ga2O3 has been studied most, however, it is hard to find materials lattice matching with β-Ga2O3 to grown epitaxial thin films for optoelectronic applications. In this work, CuGa2O4 bulk were prepared by solid state reaction as target, and the films were deposited on sapphire substrates by laser molecular beam epitaxy (L-MBE) at different substrate temperatures. The influences of substrate temperature on structural and optical properties have been systematically investigated by means of X-ray diffraction, Transmission electron microscope and UV-vis absorption spectra. High quality cubic structure and [111] oriented CuGa2O4 film can be obtained at substrate temperature of 750 °C. It’s also demonstrated that the CuGa2O4 film has a bandgap of ∼ 4.4 eV and a best crystal quality at 750 °C, suggesting that CuGa2O4 film is a promising candidate for applications in ultraviolet optoele...

Interface induced transition from bipolar resistive switching to unipolar resistive switching in Au/Ti/GaOx/NiOx/ITO structures

We report the transition from bipolar resistive switching (BRS) to unipolar resistive switching (URS) in the Au/Ti/GaOx/NiOx/ITO device at room temperature. After the proper soft breakdown of the p–n junctions (GaOx/NiOx), the switching operation could be easily transferred from BRS to URS mode. The BRS and URS behaviors are possibly related to the interfacial variation of the Ti/GaOx Schottky junction barrier and GaOx/NiOx p–n junction barrier, respectively. The high/low resistance state can be distinguished clearly and be switched reversibly under a train of voltage pulses in both BRS and URS modes. The endurance characteristics show good reliability of the stored resistance state. These results suggest a potential device for the next generation of nonvolatile memory applications.

Stabilization and enhanced energy gap by Mg doping in ε-phase Ga2O3 thin films

Mg-doped Ga2O3 thin films with different doping concentrations were deposited on sapphire substrates using laser molecular beam epitaxy (L-MBE) technique. X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and ultraviolet-visible (UV-vis) absorption spectrum were used to characterize the crystal structure and optical properties of the as-grown films. Compared to pure Ga2O3 thin film, the Mg-doped thin films have transformed from the most stable β-phase into e-phase. The absorption edge shifted to about 205 nm and the optical bandgap increased to ∼ 6 eV. These properties reveal that Mg-doped Ga2O3 films may have potential applications in the field of deep ultraviolet optoelectronic devices, such as deep ultraviolet photodetectors, short wavelength light emitting devices and so on.

The structure and magnetic properties of β-(Ga0.96Mn0.04)2O3 thin film

High quality epitaxial single phase (Ga 0.96 Mn 0.04 ) 2 O 3 and Ga 2 O 3 thin films have been prepared on sapphire substrates by using laser molecular beam epitaxy (L-MBE). X-ray diffraction results indicate that the thin films have the monoclinic structure with a \begin{document}

Epitaxial growth and solar-blind photoelectric properties of corundum-structured α-Ga2O3 thin films

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Au plasmon enhanced high performance β-Ga2O3 solar-blind photo-detector

\end{document} preferable orientation. Room temperature (RT) ferromagnetism appears and the magnetic properties of β -(Ga 0.96 Mn 0.04 ) 2 O 3 thin film are enhanced compared with our previous works. Experiments as well as the first principle method are used to explain the role of Mn dopant on the structure and magnetic properties of the thin films. The ferromagnetic properties are explained based on the concentration of transition element and the defects in the thin films.