Influence of the deposition temperature on the properties of copper and indium diselenete films deposited by spray-pyrolysis

ABSTRACT The Cu0.6In0.4Se2 films were deposited on a glass substrate by the spray-pyrolysis technique, for use as a photovoltaic cell absorber layer. The following deposition parameters were adopted: substrate temperature between 250 and 400ºC, precursor solution flow of 1 mL/min and deposition time of 30 min. The structural, electrical, morphological and optical properties of the prepared films were analyzed as a function of substrate temperature variation. X-ray diffraction analysis showed that the most intense peaks are oriented (204/220) and that the films have CuSe, CuSe2 and CuInSe2 phases. . For the electric conduction process, a single activation energy with an average value of 0.73 eV was observed. Sheet resistance ranged from 0.277 to 0.576 MΩ/□. The values of electrical resistivity presented small variations having an average value of 1.44 KΩm. The analysis of the morphology of the films made by confocal microscopy revealed that in general the samples presented no cracks, and the surfaces of films with higher deposition temperature were more uniform. The optical characterization was performed in the wavelength range of 350 to 1100 nm and the films had an absorption coefficient in the order of 103 cm-1 at the wavelength of 550 nm and optical gap with an average value of 1.5 eV.

摘要 采用喷雾热解技术在玻璃衬底上沉积了Cu₀.₆In₀.₄Se₂薄膜，用作光伏电池吸收层。本次实验采用的沉积参数如下：衬底温度区间为250~400℃，前驱体溶液流速为1 mL/min，沉积时长为30 min。研究分析了所制备薄膜的结构、电学、形貌及光学性能随衬底温度变化的规律。X射线衍射分析结果显示，最强衍射峰取向为(204/220)，薄膜中存在CuSe、CuSe₂及CuInSe₂相。电学传导过程观测到单一活化能，平均值为0.73 eV。方块电阻范围为0.277~0.576 MΩ/□。电阻率数值波动较小，平均值为1.44 kΩ·m。通过共聚焦显微镜对薄膜形貌的分析表明，整体而言所有样品均无裂纹，且较高沉积温度下制备的薄膜表面更为均匀。光学表征在350~1100 nm的波长区间内开展，薄膜在550 nm波长处的吸收系数约为10³ cm⁻¹，光学带隙平均值为1.5 eV。