Study Of The Interface Layer And Stability Of Amorphous Silicon Solar Cells

Stability is one of the factors limiting amorphous silicon (a-Si) solar cells' development. Interfaces play important role in determing the overall performance of the device. In the thesis, the effect of interface layer on the performance and the effect of process condictions for i-layer deposition on the stability have been studied. Samples were prepared on the glass substrate by PECVD system.Firstly, we have studied the effect of the interfaces on the performance of a-Si solar cells. It is found that the performance of devices with H process TCO/p or heavily dope TCO/p was improved. It is also found that the deposition of a thin a-SiC:H buffer layer between the p- and the i-layer can results in the improvement of FF to more than 70%. Five types of p/i buffer layer were fabricated and the effects of them were studied. We have also studied the relationship between the deposition time of Progresive C-buffer Layer and the effect on the device. We found that with the deposition time increasing, the efficiency of solar cells get better at first and then get worse and the efficiency have the maxmum at the 60 second.Secondly, we studied the factors that influence the stability of solar cells. We found that with the increasing of C concentration of the p/i buffer layer, the stability becomes poor. The solar cells with different deposition conditions of i-layer were fabricated and the effect of i-layer depositon conditions on stability were seen clearly. Hydrogen dilution can improve the stability of the device and when the SiH4 concentration is 6%, the stabilized efficiency is best. With the increasing of the deposition temperature, the stability gets better. And increasing the Rf-power, the stability get better at first and then become poor.