Effects of Hot Wire Temperature on Properties of GeSi:H Films with High Hydrogen Dilution by Hot-Wire Chemical Vapor Deposition
TAI Xin1, LI Xingbing2, ZHEN Huang2, SHEN Honglie3, LI Yufang3, HUANG Haibin1†1. Institute of Photovoltaics, Nanchang University, Nanchang 330031, Jiangxi, China; 2. China Intellectual Electric Power Technology (Taixing) Co. Ltd., Taixing 225400, Jiangsu, China; 3. Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, Nanjing 211100, Jiangsu, China
GeSi:H films are prepared by hot-wire chemical vapor deposition (CVD) with high hydrogen dilution, DH=98%. Effects of hot wire temperature (Tw) on deposition rate, structural properties and bandgap of GeSi:H films are studied with surface profilemeter, Raman spectroscopy, Fourier transformed infrared spectroscopy, and UV-VIS-NIR spectrophotometer. It is found that the deposition rate (Rd) goes up with increasing of Tw, but increasing rate of Rd declines when Tw≥1 550 ℃. High Tw is beneficial to the formation of Ge-Si, but it has little effect on relative contents of the hydrogen bonds (Ge-H, Si-H, etc.) in the films. In the Tw range of 1 400-1 850 ℃, the maximum bandgap of the GeSi:H films is 1.39 eV at Tw =1 450 ℃ and the band gap decreases with Tw increasing when Tw≥1 450 ℃.
Key words:GeSi:H films; hot-wire chemical vapor deposition (CVD); deposition rate; structural properties; band gap; hot wire temperature
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