Yusong Zhi

Epitaxial growth and magnetic properties of ultraviolet transparent Ga2O3/(Ga1−xFex)2O3 multilayer thin films

Multilayer thin films based on the ferromagnetic and ultraviolet transparent semiconductors may be interesting because their magnetic/electronic/photonic properties can be manipulated by the high energy photons. Herein, the Ga2O3/(Ga1−xFex)2O3 multilayer epitaxial thin films were obtained by alternating depositing of wide band gap Ga2O3 layer and Fe ultrathin layer due to inter diffusion between two layers at high temperature using the laser molecular beam epitaxy technique. The multilayer films exhibits a preferred growth orientation of crystal plane, and the crystal lattice expands as Fe replaces Ga site. Fe ions with a mixed valence of Fe2+ and Fe3+ are stratified distributed in the film and exhibit obvious agglomerated areas. The multilayer films only show a sharp absorption edge at about 250 nm, indicating a high transparency for ultraviolet light. What’s more, the Ga2O3/(Ga1−xFex)2O3 multilayer epitaxial thin films also exhibits room temperature ferromagnetism deriving from the Fe doping Ga2O3.

Construction of GaN/Ga2O3 p–n junction for an extremely high responsivity self-powered UV photodetector

A self-powered ultraviolet photodetector was constructed with GaN/Ga2O3 p–n junction by depositing n-type Ga2O3 thin film on Al2O3 single crystals substrate covered by p-type GaN thin film. The fabricated device exhibits a typical rectification behavior in dark and excellent photovoltaic characteristics under 365 nm and 254 nm light illumination. The device shows an extremely high responsivity of 54.43 mA W−1, a fast decay time of 0.08 s, a high Ilight/Idark ratio of 152 and a high detectivity of 1.23 × 1011 cm Hz1/2 W−1 under 365 nm light with a light intensity of 1.7 mW cm−2 under zero bias. Such excellent performances under zero bias are attributed to the rapid separation of photogenerated electron–hole pairs driven by built-in electric field in the interface depletion region of GaN/Ga2O3 p–n junction. The results strongly suggest that the GaN/Ga2O3 p–n junction based photodetectors are suitable for applications in secure ultraviolet communication and space detection which require high responsivity and self-sufficient functionality.

Dual-band photodetector with a hybrid Au-nanoparticles/β-Ga2O3 structure

Hybrid Au-nanoparticles (NPs)/β-Ga2O3 thin films were fabricated by laser molecular beam epitaxy of high quality β-Ga2O3 thin films on c-plane sapphire substrates followed by spin coating and post annealing of Au NPs. Photodetectors (PDs) made of hybrid Au-NPs/β-Ga2O3 thin films and bare β-Ga2O3 thin films are comparatively studied. It is found that Au-NPs can obviously improve the performances of PDs. Lower dark current, higher photoresponse and faster switching time under 254 nm light illumination are obtained by introducing Au-NPs. The localized surface plasmonic resonance from Au-NPs could be attributed to the enhanced performance. Meanwhile, a photoelectric response to 532 nm light illumination is observed in an Au NPs/β-Ga2O3 based PD. It is suggested that our hybrid Au-NPs/β-Ga2O3 PD could serve as a dual-band detector in one device.

Impurity Compensation Effect Induced by Tin Valence Change in α-Ga1.4Sn0.6O3 Thin Films

Corundum-structured α-phase Ga1.4Sn0.6O3 thin films have been deposited on m-plane Al2O3(300) substrates using laser molecular beam epitaxy technology. With increasing of the oxygen partial pressure, the crystal lattice of Ga1.4Sn0.6O3 films expands due to tin ions valence changes from Sn4+ to Sn2+. The resistivity of the film deposited under 3 × 10-5 Pa is 3.54 × 104 Ω·cm, which decreases by about 2 orders of magnitude than that fabricated under 3 × 10-1 Pa. The mixture valence of Sn2+ and Sn4+ ions leads to the impurity altitude compensation effect. The deep ultraviolet photodetector based on α-phase Ga1.4Sn0.6O3 thin films was fabricated. With the oxygen partial pressure reducing gradually, the dark current and the photocurrent increase, and the relaxation time constants diminish, respectively.

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}

Fabrication and Characterization of Two-Dimensional Layered MoS2 Thin Films by Pulsed Laser Deposition

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Structural, optical and photoluminescence properties of Pr-doped β-Ga2O3 thin films

\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.

Improvement for the performance of solar-blind photodetector based on .BETA.-Ga2O3 thin films by doping Zn

Direct growth of uniform wafer-scale two-dimensional (2D) layered materials using a universal method is of vital importance for utilizing 2D layers into practical applications. Here, we report on the structural and transport properties of large-scale few-layer MoS2 back-gated field effect transistors (FETs), fabricated using conventional pulsed laser deposition (PLD) technique. Raman spectroscopy and transmission electron microscopy results confirmed that the obtained MoS2 layers on SiO2/Si substrate are multilayers. The FETs devices exhibit a relative high on/off ratio of 5 × 102 and mobility of 0.124 cm2V−1S−1. Our results suggest that the PLD would be a suitable pathway to grow 2D layers for future industrial device applications.