本質非晶矽氫能帶隙中狀態分佈及特性參數對光電導率敏感度之計算機模擬分析

Sensitivity Analysis of the Localized Gap State Distribution on the Photoconductivity in Intrinsic Hydrogenated Amorphous Silicon

李世鴻(Shih-Fong Lee) ； 郭宗仁(Chung-Jen Kuo) ； 林寬輝(Kuan-Huei Lin)

《大葉學報》 4卷1期 (1995/12) Pp. 117-129

https://doi.org/10.7119/JDYU.199512.0117

摘要

本文使用計算機模擬對本質非晶矽氫能帶隙中狀態特性參數進行光電特性之敏感度分析。並據以探討能帶隙中狀態影響光電特性之機制，並預測其影響程度，本研究之結論與目前高品質非晶矽氫狀態特性參數相比較，並配合製程參數與材料特性之相關性研究，可明確指出改善非晶矽氫材料性質之方向。經由計算機模擬推得傳導帶尾狀態密度分佈情況，高品質非晶矽氫傳導帶尾狀態特徵能量（Eoc）必須在0.03eV以下。計算機模擬也顯示，降低價狀帶尾狀態並不是改善非晶矽氫光電導率的有效方法。而從降低懸空鍵數目著手，則可有效改善非晶矽氫光電導率。此外，計算機模擬也顯示，光電導率主要是由費米能階以下的狀態之電子截獲面積所決定。這與致敏狀態有類似的效應，這也顯示在非晶矽氫能帶隙中，只有在暗費米能階以下，才可能有電子致敏狀態的存在。

關鍵字

非晶矽氫 ； 敏感度分析 ； 計算機模擬

並列摘要

In this paper, numerical modeling was used to carry out the sensitivity analysis of the effect of gap state parameters on the photoconductivity in intrinsic hydrogenated amorphous silicon (a-Si:H). In addition, the physical mechanism of these effects was then studied to predict how the gap state parameters and optoelectronic properties were correlates. This word can identify the most important gap state parameters which, in turn, can indicate the direction of further improvement of a-Si:H properties. Based on our modeling, it is found that lowering the density of valence band tail states would not increase photoconductivity effectively. Instead, numerical modeling reveals that there is still room for further improvement of optoelectronic properties by reducing the density of dangling bond states. As far as carrier capture cross section is concerned, photoconductivity in a-Sh:H is predominately determined by the energy states below dark Fermi level. Its physical mechanism is somewhat similar to that of sensitizing states. It is also evident that the existence of sensitizing states for electron is possible only for the states below dark Fermi level.

並列關鍵字

hydrogenated amorphous silicon ； sensitivity analysis ； numerical modeling