The influence of i-ayer on the performance of HIT solar cells

• Main Authors: Yu-Wen Yen, 嚴玉雯
• Other Authors: 江雨龍
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/31264592513338851231

碩士 === 國立中興大學 === 光電工程研究所 === 100 === In this thesis, the heterojunction with intrinsic hydrogenated amorphous silicon (a-Si:H) thin layer (heterojunction with intrinsic thin layer: HIT) solar cells are investigated. The solar cells with structure of p(a-Si:H)/i(a-Si:H)/n(c-Si) are fabricated. The substrate is a typical 4-inch n-type wafer with (100) crystal orientation, 1~10 ohm-cm and about 360 μm thickness. First, HF dip and dry etching are used to passivate the surface. Second, the a-Si:H p- and i-layers are deposited by a 40.68 MHz plasma enhanced chemical vapor deposition. The a-Si:H i-layers are changed by deposition temperature and pressure to selectively control the different silicon to hydrogen (SiH) bonding configurations. The effect of various Si:H bonds on the performance of HIT solar cells are explored. Fourier-transform infrared spectra show that increase the monohydride (SiH) bonds and increasing the polyhydride ((SiH2) or (SiH2)n) bonds will reduce the hydrogen content (CH) and increase the real and imagine of dielectric constants (Ɛ1 and Ɛ2). I-V measurements indicate that the a-Si:H i-layers of HIT solar cells with low microstructure (RS = (SiH2/(SiH+SiH2)) can increase the fill factor, short-circuit current and energy transfer efficiency. Low-RS a-Si:H films are denser and have low defect densities. The passivation of p/i interface by low-RS a-Si:H i-layer can reduce the recombination at the interface and in the bulk of i-layer. Adding a-Si:H i-layer at the p/i interface can effectively passivate the bonding defects due to formation of heterojunction. Reducing the interface recombination significantly increase the open-circuit voltage, short-circuit current and fill factor. Inserting a thin a-Si:H i-layer with more SiH bonds can improve the performance of HIT solar cells.