Use rapid thermal annealing process to improve the contact between the metal electrode and a-Si:H film of solar cell.

• Main Authors: Hsueh-Yeh Lu, 呂學燁
• Other Authors: JHENG-YANG CHANG
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/75200106448207971989

碩士 === 國立中央大學 === 光電科學研究所 === 99 === The hydrogenated amorphous silicon (a-Si:H) structure with a short range order; it has simple fabrication process, low cost, and large area. It has been extensively used in semiconductor components and thin film solar cells. However, the conversion efficiency of the a-Si:H solar cell is much lower than the crystalline silicon solar cell due to the much higher defects. Improving the conversion efficiency of a-Si:H solar cells by structures or materials is an important issue. We deposit a-Si:H thin films and corresponding solar cells (with structure of glass/ITO/p-i-n/Ag) by PECVD（Plasma Enhanced Chemical Vapor Deposition, PECVD）. This thesis is divided into two issues. First is the influence of thickness of a-Si:H i layer while the other parameters are kept identical. Because the thickness of i layer decides the absorption of sunlight and electronics properties in the solar cell, we probe the thickness effect of i layer from 440nm to 620nm. We find that the optimized i layer thickness is 530nm. Second, the contact between the metal electrode and a-Si:H film is improved by thermal anneal process in relatively low temperature. The series resistance of solar cells is lower after the thermal anneal process; we conclude that a ohmic contact forms between metal electrode and a-Si:H film. Additionally, the dangling bond at surface of a-Si:H film can be eliminated through the rapid annealing process; the passivation process lowers the recombination rate of free carriers at interfaces. The contact resistance (RC) between the metal electrode and a-Si:H film reduces to 17.11kΩ from 6.325kΩ and the series resistance (RS) of the solar cells reduces to 114.8Ω from 170.5Ω and the shunt resistance (Rsh) of the solar cells increase to 3771.5Ω from 2232.6Ω with the temperature anneal process at 300°C in 2 minutes; meanwhile the conversion efficiency increases to 3.784% from 3.161%.