The influence of microdoping technique on the photodegradation of hydrogenated amorphous silicon p-i-n solar cells

• Main Authors: Chao-Hsien Tseng, 曾昭憲
• Other Authors: 江雨龍
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/38825582911588228445

碩士 === 中興大學 === 電機工程學系所 === 94 === In this thesis, we will investigate the influence of the intentional and unintentional microdoping impurities on the photodegradation of hydrogenated amorphous silicon (a-Si:H) p-i-n thin-film solar cells. A-Si:H films and solar cells will be fabricated using a capacitive-type PECVD. The unintentional microdoping impurities are mainly oxygen atoms, which are coming from the outgassing of the reactor of PECVD and the impurities of reaction gases. The increase of oxygen impurities doped into a-Si:H films depends on the decreasing of deposition rate. Both hydrogen dilution and pulse-wave modulation RF power techniques will be used to control the deposition rate, and to alter the concentration of oxygen impurities. The p/i and i/n interfaces of a-Si:H p-i-n solar cells are microdoping by O atoms. The photodegradation of these solar cells with microdoping impurities will compare with the reference cell without microdoping impurities to explore the influence of this technique on the photodegradation effect. We expect that this effect can be reduced by compensation the light-induced space charges at the p/i and i/n interfaces by the microdoping O impurities. High film density and low defects hydrogenated microcrystalline silicon (μc-Si:H) films were fabricated by plasma-enhanced chemical vapor deposition, and were inserted at the i-n interface of the a-Si:H p-i-n solar cells to improve the performance of the cells. By inserting a 3-nm-thickness μc-Si:H layer with the crystal volume ratio of 64% into the i-n interface of an a-Si:H p-i-n solar cell, the open-circuit voltage, short-circuit current, fill factor and energy transfer efficiency are significantly increased by this μc-Si:H layer. The passivation of the defect densities at the i-n interface reducing the carrier recombination and increasing the activation of the doping atoms at the i-n interface can effectively improve the performance of the cell.