Studies On The Synthesis And Properties Of Nanocrystalline Sili Con Thin Film Solar Cell

At present, human beings are facing with severeenvironmental pollution and energy crises. Developing clean andrenewable energy resources is imminent. As an inexhaustibilityand sanitary energy, solar energy provides a promising prospecton the coming development way. By2010, the total powergenerated by the solar cell in the whole world has reached4GW;the growth rate almost reached30%every year. Nowadays, themost popular solar cell is silicon based on solar cells, such ascrystalline silicon solar cell and amorphous silicon solar cell.However, the crystalline silicon solar cell is expensive, and theamorphous silicon solar cell has the problem of light attenuation.And other compound thin film solar cells could causeenvironmental pollution problem. The hydrogenated nano-crystalline silicon （nc-Si:H） thin film solar cell can avoid allthese shortcomings, so it is getting more and more attention byresearchers.Hydrogenated nano-crystalline silicon （nc-Si:H） thin film is akind of nano silicon material which composes of nano-scaledsilicon grains embedded in Si:H amorphous tissues. Because ofnano scale effect, the film has super phototoxic, optoelectronicproperty and high electric conductivity, photo absorptioncoefficient, optical band gap. Also compared with the a-Si:Hsolar cell, it has no S-W effect. The optical band gap of nc-Si:Hcan be tuned by the crystallization ratio and the nanocrystallinegrain size according to the quantum size effect. So it can beprepared in the （nc-Si:H） thin film solar cell because of itsexcellent properties.The nc-Si:H（N）/c-Si（P） heterojunction solar cell display the advantage of high mobility of crystalline silicon, and in the lowtemperature of thin film deposition process. The preparationprocess of solar cell is simple, and it has the development ofprospects to achieve low cost and high efficiency solar cell.The main research contents of this paper are as follows:1. Phosphorus-doped hydrogenated silicon （nc-Si:H） films wereprepared by plasma enhanced chemical vapor deposition （PECVD）technique. The effects of phosphine, silane concentration, power,temperature on the crystallizeation ratio, nanocrystalline grain size,electric conductivity and optical band gap of the （nc-Si:H） filmwere analyzed. The micro-structures and optoelectronic properties ofthe （nc-Si:H） films were optimized by adjusted the processparameters. So it can be prepared for HIT heterojunction solar celland p-i-n thin film solar cell.2. The elements and the preparation process of nc-Si:H（N）/a-Si:H（I）/c-Si （P） heterojunction film （HIT） solar cell wereintroduced. The phosphine concentration and thickness of n-typed layeron the effects of solar cell’s characteristics were researched. The effect ofthe intrinsic layer, Al₂O₃passivation layer on the properties of solar cellwere investigated.