Effect of temperature on structural and optical properties of ZnS thin films by chemical bath deposition without stirring the reaction bath

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• 作者：Huan Ke ; Shuwang Duo ; Tingzhi Liu ; Qi Sun ; Chengxiang Ruan ; Xiaoyan Fei ; Jilin Tan ; Sheng Zhan
• 关键词：Zinc sulfide ; Thin films ; Chemical bath deposition ; Optical properties
• 刊名：Materials Science in Semiconductor Processing
• 出版年：February, 2014
• 年：2014
• 卷：18
• 期：Complete
• 页码：28-35
• 全文大小：2059 K

文摘

ZnS thin films were deposited at different temperatures on glass substrates by chemical bath deposition method without stirring the deposition bath. With deposition temperature increasing from 50 掳C to 90 掳C, pH decreases rapidly, homogeneous precipitation of ZnS, instead of Zn(OH)₂ easily forms in the bath. It means that higher temperature is favorable for the formation of relatively high stoichiometric film, due to the lower concentration of OH^{鈭?/sup>. The thickness of the films deposited at 90 掳C is much higher than that of the films deposited at 50 掳C and 70 掳C. Combining the film thickness with the change of pH, the growth of film, especially deposited at 90 掳C mainly comes from the fluctuation region of pH. At the same time, with the increase of deposition temperature, the obtained films are transparent, homogeneous, reflecting, compact, and tightly adherent. The ZnS films deposited for 1.5 h, 2 h and 2.5 h at 70 掳C and 90 掳C have the cubic structure only after single deposition. The average transmission of all films, especially the thicker films deposited at 90 掳C, is greater than 90% for wavelength values in the visible region. Comparing with the condition of stirring, the structural and optical properties of films are improved significantly. The direct band gaps range from 3.93 to 4.06 eV.}