Improvement of haze ratio of DC (direct current)-sputtered ZnO:Al thin films through HF (hydrofluoric acid) vapor texturing

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• 作者：Youn-Jung Lee^a ; Hyeongsik Park^a ; Minkyu Ju^a ; Youngkuk Kim^c ; Jinjoo Park^a ; Dao Vinh Ai^a ; S. Qamar Hussain^b ; Youngseok Lee^b ; Shihuyn Ahn^a ; Junsin Yi^a ; ^b ; ^{yi@skku.ac.kr" class="auth_mail} ; ^{yi@yurim.skku.ac.kr" class="auth_mail}
• 关键词：ZnO ; Al ; Texture ; Haze ; High transmittance ; Vaporized HF ; Thin film Si solar cell
• 刊名：Energy
• 出版年：1 March, 2014
• 年：2014
• 卷：66
• 期：Complete
• 页码：20-24
• 全文大小：1249 K

文摘

The textured ZnO:Al films are used to enhance light trapping in thin film solar cells. The wet etch process is used to texture ZnO:Al films by dipping in diluted acidic solutions such as HCl (hydrogen chloride acid) or HF (hydrofluoric acid). During this process, the acidic solution can damage the glass substrate, which could then be difficult to apply for the inline mass production process since this process needs to be performed outside the chamber. In this paper we report a new technique to control the surface morphology of DC-sputtered ZnO:Al films. The ZnO:Al films are textured with vaporized HF formed by mixing the HF with an H₂SiO₃ solution. We achieved a high haze value of 74.6% at a 540聽nm wavelength by increasing the etching time and HF concentration. A haze value of about 58% was achieved at a 800聽nm wavelength when vapor texturing was used. The ZnO:Al film texture by HCl had a haze ratio of about 9.5% at 800聽nm and less than 40% at 540聽nm. In addition to a low haze ratio, in the texturing by HCl it was very difficult to control etching and to keep reproducibility due to its very fast etching speed.