A buffer-layer/a-SiO_x:H(p) window-layer optimization for thin film amorphous silicon based solar cells

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• 作者：Jinjoo Park ; Vinh Ai Dao ; Chonghoon Shin ; Hyeongsik Park ; Minbum Kim ; Junhee Jung ; Doyoung Kim ; Junsin Yi
• 关键词：Buffer-layer/a-SiOx ; H(p) window-layer ; Schottky barrier height ; Built-in potential ; Inversion of activation energy
• 刊名：Thin Solid Films
• 出版年：2013
• 出版时间：1 November, 2013
• 年：2013
• 卷：546
• 期：Complete
• 页码：331-336
• 全文大小：858 K

文摘

Amorphous silicon based (a-Si:H-based) solar cells with a buffer-layer/boron doped hydrogenated amorphous silicon oxide (a-SiO_x:H(p)) window-layer were fabricated and investigated. In the first part, in order to reduce the Schottky barrier height at the fluorine doped tin oxide (FTO)/a-SiO_x:H(p) window-layer heterointerface, we have used buffer-layer/a-SiO_x:H(p) for the window-layer, in which boron doped hydrogenated amorphous silicon (a-Si:H(p)) or boron doped microcrystalline silicon (¦Ìc-Si:H(p)) is introduced as a buffer layer between the a-SiO_x:H(p) and FTO of the a-Si:H-based solar cells. The a-Si:H-based solar cell using a ¦Ìc-Si:H(p) buffer-layer shows the highest efficiency compared to the optimized bufferless, and a-Si:H(p) buffer-layer in the a-Si:H-based solar cells. This highest performance was attributed not only to the lower absorption of the ¦Ìc-Si:H(p) buffer-layer but also to the lower Schottky barrier height at the FTO/window-layer interface. Then, we present the dependence of the built-in potential (V_bi) and blue response of the devices on the inversion of activation energy (¦Î) of the a-SiO_x:H(p), in the ¦Ìc-Si:H(p)/a-SiO_x:H(p) window-layer. The enhancement of both V_bi and blue response is observed, by increasing the value of ¦Î. The improvement of V_bi and blue response can be ascribed to the enlargement of the optical gap of a-SiO_x:H(p) films in the ¦Ìc-Si:H(p)/a-SiO_x:H(p) window-layer. Finally, the conversion efficiency was increased by 22.0 % , by employing ¦Ìc-Si:H(p) as a buffer-layer and raising the ¦Î of the a-SiO_x:H(p), compared to the optimized bufferless case, with a 10 nm-thick a-SiO_x:H(p) window-layer.