Polycrystalline Silicon Thin Film Battery Prepared

Polycrystalline silicon thin film solar cell has the advantages of both crystalline silicon solar cell and thin film solar cell, so it is believed as one of the best candidate of " the second generation of solar cells ".The grain size has great influence on the efficiency of thin film solar cells. The high temperature method can deposit films with larger grains and better film, so it is promising to get high efficiency. In this paper, we adopted rapid thermal chemical vapor deposition (RTCVD) and zone melting recrystallization (ZMR) methods to deposit polycrystalline silicon thin films and studied the preparation technologies of the solar cells on SiSiC and Al₂O₃ ceramic substrates by high temperature method.In this paper, RTCVD method is used not only to prepare silicon seeding layer, which is treated following by ZMR to enlarge the grain size , but also to grow the polycrystalline silicon film as active layer. We have studied the effects of substrate materials, deposition temperature and the SiH₂Cl₂ flux on deposition rate, surface morphology and the grain size of polycrystalline silicon thin film. Changes of surface morphology, crystalline structure and electrical properties of silicon thin films after ZMR have been analysed. We have prepared the diffusion barrier layers, p-n junction and electrodes. At last, we use the PC1D program to simulate polycrystalline silicon thin film solar cells prepared under high temperature.The main results obtained in this paper are as follows: The quality of polycrystalline silicon thin films are good on SiSiC and Al₂O₃ substrates deposited by RTCVD, and the grain size are about several micrometers. The structure of thin film deposited on SiSiC is more dense than that on Al₂O₃ substrate. The grain size of silicon films is larger when deposition temperature is higher. SiH₂Cl₂ flux have important influence on the deposition rate of polycrystalline silicon thin film , but which is little affected by substrates. After zone melting , the grain size becomes larger and the films have preferential crystalline orientations which is <111> onAl₂O₃, but is <400> on SiSiC substrate. The electrical properties of thin films are improved after ZMR, Such as the resistivity is reduced by one magnitude. Carrier density of the...