Improvements of Amorphous Si-Alloy Based Thin-Film Solar Cells with H2/O2- Plasma Treatments on Transparent Electrode and Deposition of i-a-SiGe:H Light Absorption Layer at Low Pressure

• Main Authors: Jhong-Hong Cyue, 闕仲宏
• Other Authors: Jyh-Wong Hong
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/bdbr48

碩士 === 國立中央大學 === 電機工程研究所 === 96 === In this thesis, the H2/O2-plasma treatments on transparent indium-tin-oxide (ITO) electrode and deposition of i-a-SiGe:H absorption layer at low pressure have been used to improve the performance of amorphous Si-alloy based thin-film solar cells. Firstly, since that the series resistance between the ITO electrode and amorphous layer plays an important role in the performance of a solar cell, the in-situ plasma treatments was employed to improve the contact and it was found that the performance of a p-i-n a-Si:H thin-film solar cell could be enhanced with the H2-plasma (100 W, 0.4 torr, 25 ℃ and 5 min.) and then O2-plasma (55 W, 0.15 torr, 25 ℃ and 5min.) treatments on ITO electrode. This was due to the combination of H2- and O2-plasma treatments could remove the hydrocarbon compounds and increase the work function of ITO electrode. Hence, the Schottky barrier height between the ITO and amorphous layer could be lowered. In addition, the i-a-SiGe:H absorption layer was deposited at a lower pressure of around 0.25 torr with a plasma-enhanced chemical vapor deposition system, to reduce the amount of Si=H2 bonds in the film and hence improve the performance of graded ITO/p-SiC:H/buffer layer (i-a-SiC:H)/i-a-Si:H/interface layer/i-a-SiGe:H/n-a-Si:H/Al solar cell. In this study, the highest obtainable conversion efficiency of this graded solar cell was 3.63 %.