Double window layers on the performance of a-Si:H solar cells

• Main Authors: Yi-Chih Kuo, 郭翼誌
• Other Authors: 江雨龍
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/03001214575224297591

碩士 === 國立中興大學 === 光電工程研究所 === 103 === In this thesis, various optical energy bandgap (Eg) of a-SiCx:H:By p-layers were combined to form single and double window layers for hydrogenated amorphous silicon (a-Si:H) p-i-n thin film solar cells, and its influence on the performance of solar cells were investigated. The Eg of a-SiCx:H:By p-layers were controlled by adding carbon atoms and reducing Si atoms in the layers. The first p-layer was connected with transparent conductive oxide (TCO) layer which was low Eg and named A-layer. The second p-layer was connected with i-layer which was high Eg and named B-layer. For combinations of Eg of p-layers were (1) modulation of Eg and thickness of A/B to form the equivalent Eg of 2.0 eV, (2) reduction thickness of B-layer to ultra thin of 5 Å, (3) fixed thickness ratio of 75 Å/25 Å, change Eg ratio of A/B, and (4) fixed Eg of A/B to 1.7 eV/2.1 eV, change thickness ratio of A/B. Using these four combinations of double p-layer window layers to investigate the influence on the efficiency of solar cells. The results of (1) shown that as the Eg of B-layer larger than 2.5 eV, more photons could penetrate into i-layer to increase the short-circuit current density (Jsc). However, the film was more defects to significantly reduce the fill factor (FF) and open-circuit voltage (Voc). The efficiency of solar cell was significantly reduced. The results of (2) demonstrated that reduction of thickness of high Eg of B-layer (> 2.5 eV) could reduce the decreasing of FF and Voc. The results of (3) indicated that low Eg of A-layer could improve FF, and the low defect of high Eg of B-layer should be used. In this study, the best Eg ratio of A/B was 1.7 eV/2.1 eV. The results of (3) shown that increase thickness of A-layer and decrease thickness of B-layer could result in reduction of Jsc and Voc but increase of FF. There was an optimization of thickness ratio of A/B layers. For this study, the highest efficiency cell was 1.7(25 Å)/2.1(75 Å) double window layer, the Jsc, Voc, FF and  was 12.10 mA/cm2, 0.83 V, 63.31% and 6.33%, respectively.