Preparation and mechanism analysis of polycrystalline silicon thin films with preferred orientation on graphite substrate

In this paper, we prepared polycrystalline silicon (poly-Si) thin films on polished graphite substrate by magnetron sputtering and systematically investigated the effects of substrate temperature and deposition time on preparation of poly-Si thin films. The poly-Si thin films were characterized by X-ray diffraction, Raman spectroscopy (Raman) and Scanning electron microscopy, which showed that the samples presented high crystallization quality. The mechanisms of Si(220) preferred orientation and the conversion from Si(220) to Si(111) were explained by Principle of the lowest energy, Bravais rule and the Classical nucleation theory. We can prepare poly-Si thin films with Si(111) or Si(220) preferred orientation by controlling the substrate temperature and deposition time, which is important for preparing high efficient solar cells.