Xi-Jian Zhang

Shandong University, Chi-nan-shih, Shandong Sheng, China

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Publications (7)14.7 Total impact

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    ABSTRACT: We have investigated the thermal stability of GaN powders using DTA–TG, XRD, and XPS. GaN powders have been treated below 1400°C in the flowing stream of N2 gas. The pure GaN powders is indecomposable below 1120°C, but annealing at 1050°C results in the degradation of the crystalline quality of the GaN powders. With the increase of the temperature, more and more GaN powders are separated into Ga metal in the temperature range of 1120–1312°C, but the decomposition of GaN is propitious to improvement of the crystalline quality of GaN. When the temperature exceeds 1312°C, all the GaN powders are converted into Ga metal. The morphology of the samples obtained in the different temperature regimes was investigated using SEM. The results indicate that the average size of the samples obtained at the decomposition temperature regimes of the GaN powders is bigger.
    Materials Chemistry and Physics 11/2007; 106(1):5-7. DOI:10.1016/j.matchemphys.2007.04.063 · 2.13 Impact Factor
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    ABSTRACT: Beta-gallium oxide (β-Ga2O3) powders have been synthesized through simple thermal annealing gallium nitride (GaN) powders in the opening air at 900°C. The course of β-Ga2O3's formation and its structural properties were studied by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photo-electron spectroscopy (XPS). The observations revealed that Ga2O3 on the surface of GaN particles has been formed below 500°C, the rate of Ga2O3's formation under air is slow in the temperature range from 500 to 800°C and is fast in the temperature range of 800–900°C. The as-obtained products at 900°C are pure, single-crystalline monoclinic Ga2O3 particles, and the size of β-Ga2O3 is about 50–300nm.
    Materials Chemistry and Physics 01/2007; 101(1):99-102. DOI:10.1016/j.matchemphys.2006.02.021 · 2.13 Impact Factor
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    ABSTRACT: Different photoluminescence (PL) spectra are observed for rf magnetron sputtered polycrystalline Mg0.25Zn0.75O and Mg0.37Zn0.63O films on silicon substrates when excited by different wavelengths. When the excitation wavelength is 280 nm, a UV emission peak at 370 nm and a blue peak at 462 nm are generated for the Mg0.25Zn0.75O film, and those two peaks for the Mg0.37Zn0.63O film shift to 366 nm and 466 nm, respectively. The wavelengths of the PL peaks are related to the excitation wavelength. The stronger peak is obtained in the blue band due to a large number of oxygen vacancies caused by excess Zn and Mg atoms, while the weaker peak is obtained in the ultraviolet band.
    Chinese Physics Letters 11/2005; 22(11):2973-2976. DOI:10.1088/0256-307X/22/11/069 · 0.95 Impact Factor
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    ABSTRACT: Gallium nitride(GaN) powders have been synthesized by nitriding gallium oxyhydroxide (GaO2H) powders in the flow of NH3 gas at a nitridation temperature of 950 °C for 35 min. X-ray powder diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectra reveal that simple heat treatment of GaO2H in the flow of NH3 leads to the formation of hexagonl GaN with lattice constants a=3.191 Å, and c=5.192 Å at 950 °C through intermediate conversion of β-Ga2O3. X-ray photo-electron spectroscopy (XPS) confirms the formation of bonding between Ga and N, and yields that the surface stoichiometry of Ga:N approximates 1:1. Transmission electron microscopy (TEM) image indicates that GaN particle is a single crystal, and its morphology is ruleless.
    Diamond and Related Materials 10/2005; 14(10):1730-1734. DOI:10.1016/j.diamond.2005.06.024 · 1.57 Impact Factor
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    ABSTRACT: ZnO/Mg0.16Zn0.84O (ZnO/MgZnO) films are fabricated on x-cut and z-cut LiNbO3 (LN) substrates by radio-frequency magnetron sputtering. High transparencies are confirmed by a spectrophotometer. X-ray diffraction (XRD) spectra show that all the films are c-axis oriented. The waveguiding properties, as well as the refractive indices and thickness of the films are demonstrated and determined by prism coupling. Both transverse electric (TE) and transverse magnetic (TM) modes are measured at lambda=0.633 mum and 1.539 mum, respectively. The waveguide loss is measured at lambda=0.633 mum with a fiber probe technique. The experimental results show that high optical quality ZnO films can be obtained with MgZnO buffer layers.
    Optics Express 07/2005; 13(13):5093-9. DOI:10.1364/OPEX.13.005093 · 3.53 Impact Factor
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    ABSTRACT: Gallium oxyhydroxide (GaO2H) nanorods were synthesized from ball-milled gallium nitride (GaN) powders. X-ray diffraction (XRD) revealed that the synthesized GaO2H is orthorhombic crystal structure with lattice constants a=4.588 Å, b=9.812 Å and c=2.979 Å. Transmission electron microscopy (TEM) and corresponding selected area electron diffraction (SAED) pattern showed that the surface morphology of GaO2H displayed a single phase particles with short rod, and size range of GaO2H particles is from 10 to 80 nm. Fourier transform infrared (FTIR) confirms that the samples contain the binding of Ga–O and Ga···H–O–Ga.
    Materials Letters 12/2004; 58(30):3925-3928. DOI:10.1016/j.matlet.2004.08.020 · 2.27 Impact Factor
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    ABSTRACT: Gallium nitride(GaN) powders have been synthesized by nitriding β-Ga2O3 powders in the flow of NH3 gas at a nitridation temperature of 950 °C for 35 min. X-ray powder diffraction (XRD) reveals that the synthesized GaN is of a single-phase wurtzite structure with lattice constants a = 3.191 Å. and c = 5.192 Å. Transmission electron microscopy (TEM) also indicates that GaN particle is a single crystal. X-ray photo-electron spectroscopy (XPS) confirms the formation of bonding between Ga and N, and yields the surface stoichiometry of Ga:N of 1:1. The morphology of GaN particles examined by scanning electron microscopy (SEM) is ruleless.
    Materials Chemistry and Physics 11/2004; 88(1-88):180-184. DOI:10.1016/j.matchemphys.2004.07.004 · 2.13 Impact Factor