本論文的主要目的是利用氫氣與氬氣稀釋的技巧沉積光電特性較優良的非晶矽及非晶矽鍺薄膜，並據以改善非晶質矽基太陽電池的特性。 首先，我們探討氬氣稀釋對非晶矽太陽電池特性的影響。以前的許多研究結果顯示，利用高氫氣稀釋比例的電漿助長化學氣相沉積(PECVD)方法可改善非晶矽薄膜的穩定性。然而大量氫氣源氣體矽烷(SiH4)混合物是有相當的危險性。相較之下，利用氬氣稀釋法是比較安全的。這是研究與採用氬氣稀釋法的主要原因。本實驗研究結果顯示利用氬氣稀釋法沉積的非晶矽薄膜具有較佳的光吸收特性，且利用氬氣稀釋法研製的非晶矽太陽電池亦具有較高的短路電流。 接著我們探討氫氣稀釋，氬氣稀釋及調整源氣體鍺烷(GeH4)的流量對非晶質薄膜光電特性的影響，改善非晶矽鍺薄膜的吸光率，並且提高含非晶矽鍺薄膜之太陽電池的短路電流。 最後，我們使用改良後的非晶矽和非晶矽鍺薄膜的製程來研製梯度能階的非晶質矽基太陽電池。此太陽電池的轉換效率可達到百分之 1.58。 In this thesis, the hydrogen and argon dilution technique was employed to deposit the a-Si:H and a-SiGe:H films with better optoelectronic characteristics, and then these thin-films were used to improve the photovoltaic parameters of amorphous silicon based solar cells. First, the process conditions for depositing a-Si:H films with argon dilution of silane (4% in H2) were studied. Researches to improve stability of hydrogenated amorphous silicon (a-Si:H) thin films deposited with a plasma-enhanced chemical vapor deposition (PECVD) system and to increase the conversion efficiency of solar cells have led to the use of highly diluted silane in hydrogen . However, the hydrogen–silane mixture is quite dangerous and the advantage of argon dilution of silane lies in the fact that it is a much safer process. That is why the possibility to obtain stable and device grade thin-films using argon dilution of silane has been investigated. In this study, we found that the absorptance spectrum of i-a-Si:H deposited with argon dilution technique was better than that of the one without argon dilution, and the a-Si:H p-i-n solar cell fabricated with argon dilution technique had higher short-circuit current density(Jsc). Then, the effects of hydrogen dilution, argon dilution and GeH4 gas flow-rate on the properties of amorphous films were investigated. The absorptance spectrum of i-a-SiGe:H thin-film was improved also. The (Jsc) for amorphous p(Si)-i(SiGe)-n(Si) solar cell fabricated with the developed technique was increased also. Finally, these better i-a-Si:H and i-a-SiGe:H films deposition process conditions for i-a-Si:H and i-a-SiGe:H films were used to fabricate graded gap amorphous silicon based solar cells. The solar cell had an obtainable conversion efficiency = 1.58 % under AM 1.5 illumination.
