Silicon Film Solar Cell Trapping And Silicon HIT Cell Fabrication Research

Silicon thin film solar cells have attracted wide attention due to its relatively low material cost. However, since smaller thickness it cannot absorb sun light completely. So, the light trapping is very importance. Si HIT (heteroj unction intrinsic thin layer) solar cell firstly fabricated by Panasonic Corporation of Japan has been paid more attention because of its high efficiency and low cost. In this dissertation, the light trapping of Si thin film solar cells and the fabrication technology of Si HIT cells were studied.The influence of relative lateral shift between the front and back period textures on the light absorption of microcrystalline silicon thin film solar cells was studied using finite difference time domain (FDTD) method. A concept of lateral matching between the front and back textures was proposed. In most cases, an introduction of relative lateral shift between the front and back textures can effectively enhance the light absorption in silicon thin film cells and the total light absorptivity can be increased by 8.0 percentage.The influence of Al nanopits size and distance of the back electrode of amorphous silicon thin film solar cell was studied by FDTD. With the increase of Al nanopit size, absorption of the Si thin films solar cells changes little in short wavelength range (300-550nm), and it increases in long wavelength range (550-800 nm) due to the appearance of more and wide interference peaks. The maximum light absorption of the Si thin film solar cell can be improved to 70.8%.The fabrication technology of Si HIT cell was studied, and the important factors and its order affecting the performance of the cell were found. Hydrogen plasma treatment on the Si wafer surface has a very important influence on the performance of the cell, and it is the first process should to be payed attention. The other process are:the deposition of I layer, the fabrication of Al back electrode, the removing of damage layer of Si wafer, and the fabrication of front silver grating electrode. The mechanism of the influence of these processes on the performance of the HIT cell was analyzed. A Si single side HIT cell with the efficiency of 13.08%was obtained by optimizing various process conditions.