The graded SiGe absorption layer solar cell deposited by Laser-Assisted Plasma EnhancedChemical Vapor Deposition

• Main Authors: Kuan-FuLu, 呂冠輹
• Other Authors: Ching-Ting Lee
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/41786554359279583524

碩士 === 國立成功大學 === 微電子工程研究所碩博士班 === 100 === In general, a solar cell structure consists of an absorber layer, in which the photons of an incident radiation are efficiently absorbed resulting in a creation of electron-hole pairs. The photo-generated electrons and holes are driven by the built-in electric field of the junction to form the photo-current. The transmission capacity of electron was much better than the hole. Therefore, before the holes were driven to the contacts, the holes were recombined at defects. As this result, the photo-current is diminished. On other words, to obtain high performance, the transmission capacity of hole should be improved. On the other hand, the transmission capacity is determined by the built-in electric field, in which it should be as high as possible . In this study, the a-SiGe thin film was applied to the absorber layer of solar cells. The energy band-gap of amorphous silicon–germanium (a-SiGe) alloy can be adjusted continuously between 1.4 eV and 1.8 eV by varying the Ge fraction. This characteristic renders a-SiGe a suitable light absorber material in multi-junction amorphous silicon (a-Si) based thin film solar cells, in which the a-SiGe acts as intrinsic layer in middle or bottom cells to enhance green to red absorption . The high performance silicon-germanium (a-SiGe) solar cells with graded absorber layer and microcrystalline structure doped thin films (p-Si and n-Si) was fabricated by using laser-assisted plasma-enhanced chemical vapor deposition (LAPECVD) system. These experimental results verified that the solar cells with graded absorber layer was improved from 19.43 mA/cm2 to 23.54 mA/cm2. Consequently, the conversion of the solar cells efficiency was upgraded from 5.46 % to 6.83 %. Furthermore, the short circuit current density of the solar cells with graded absorber and microcrystalline structure doped thin films (p-Si and n-Si) layer was improved from 19.43 mA/cm2 to 26.3 mA/cm2. Consequently, the conversion of the solar cells efficiency was upgraded from 5.46 % to 7.51 %.