| At present, Monocrystalline silicon, polycrystalline silicon solar cell occupy the90%market share, due to the preparation of solar cells is complex, high cost, high energy consumption and high temperature process, which restricts the popularization and application. Compared with monocrystalline silicon and polycrystalline silicon solar cells, silicon thin film solar cells is a kind of cell with materials saving, the material and cell once molding, simple process,less energy consumption, low cost, which has a broad development prospects. Amorphous silicon thin film solar cells get big promotion in the market because of its’high light absorption and can be depositing on the cheap or flexible substrate in large scale in the low temperature to decrease the cost greatly. But the conversion efficiency of amorphous silicon solar cells compared to crystalline silicon cells generally is not high. In the laboratory, the highest conversion efficiency is only13%. The efficiency of cell on the production line is less than10%. And under the certain condition of light, the transform efficiency will decline(light-induced degradation effect). It greatly limits the application. In order to better play to the benefit of the amorphous silicon materials, It is necessary to further improve the quality of the amorphous silicon thin film materials,study the preparation process of thin materials. For instance, further increase the infrared light absorption of materials from the sun, reduce the density of defect states and small crystalline grain size Especially pay attention to improve the metastable structure of amorphous silicon thin film, and improve the stability of the film to improve the stability of amorphous silicon thin film materials. At current, Preparation technologies of amorphous silicon thin film include plasma chemical vapor deposition, magnetron sputtering, and hot wire vapor deposition etc. But in the industrial production line, it mainly uses radio frequency (rf) chemical vapor deposition technique. In this paper, using the conventional RF-PECVD, by controlling the deposition parameters to optimize the quality of the film and making much hydrogen into the chamber to increase the hydrogen dilution and crystalline grain size to improve the stability of the films, increasing of hydrogen content in the film, using the hydrogen to passivate the dangling bonds inside silicon films to improve the optical and electrical properties and all the properties were characterized.In this paper, the author simply introduces the development of solar cells, the characteristics of amorphous silicon thin film, the preparation and characterization of amorphous silicon thin film. Through the experiment, using radio frequency (rf) plasma enhanced chemical vapor deposition technique, by changing the radio frequency power and deposition pressure, to understand the influence of these two parametersThe results show that under the condition of relatively low deposition pressure, amorphous silicon thin film deposition rate is first increasing then decreasing,the change of optical band gap width opposite to it. The dark conductivity of film material is decreasing with the increase of power first, then decreasing. The performance of the photosensitive is opposite to it. And under the condition of low RF-power, the thin film is more likely to be oxidized. But under the lower RF-power, changing the pressure, the deposition rate is increasing and reach a certain value, the change is not obvious, the optical band gap is decreasing and then increasing, and it changes slowly. Dark conductivity performance is a decreasing trend, the increase of photosensitivity have a process which increase and then decrease. Finally choose a relatively low pressure and low power conditions for SEM test, it found the film in a small grain growth without any growth trend and it exhibits homogeneous isotropic growth... |
PDF Full Text Request