Influence of N₂ and O₂ annealing treatment on the optical bandgap of polycrystalline Ga₂O₃:Cu films

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• 作者：Yi Cheng ; Hongwei Liang ; Yang Liu ; Xiaochuan Xia ; Rensheng Shen ; Shiwei Song ; Yunfeng Wu ; Guotong Du
• 关键词：Cu-doped Ga2O3 thin film ; X-ray diffraction ; Optical bandgap ; Amorphous phase ; Surface morphology
• 刊名：Materials Science in Semiconductor Processing
• 出版年：2013
• 出版时间：October, 2013
• 年：2013
• 卷：16
• 期：5
• 页码：1303-1307
• 全文大小：2305 K

文摘

Cu-doped Ga₂O₃ thin films were deposited by electron beam evaporation with subsequent annealing at 1000 ¡ãC in N₂ and O₂ for 1 h. The influence of the annealing atmosphere on the crystal structure, surface morphology and optical properties of Ga₂O₃:Cu films was investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), and transmittance and photoluminescence (PL) spectroscopy. The optical bandgap deduced from the absorption spectrum was greater for the O₂ annealed than for N₂ annealed samples. In both cases the bandgap was wider than for bulk ¦Â-Ga₂O₃. The grain size and surface roughness were sensitive to the annealing atmosphere. Results confirmed that the annealed samples were polycrystalline ¦Â-Ga₂O₃ with some amorphous phase. We hypothesize that annealing in oxygen led to recrystallization of the Ga₂O₃:Cu film. Annealing treatment improved the crystal quality of Ga₂O₃:Cu films and the PL intensity of the samples increased.