Preparation And Its Structure Of Nanocrystalline Silicon Films In High-efficiency Films Solar Cells

Recently, to improve energy conversion efficiency, the researchers advanced the concept of the third generation solar cells. The third photovoltaic solar cells are to make full advantage of the spectrum of the Sun. For the tradition cells, Ultraviolet radiation is either permeated directly or absorbed by the silicon facilities, which invert into heat energy but not electricity. These may be effect the life of the batteries. The research showed that Ultraviolet radiation can be combined with nc-Si particles and produce electricity. Professor Munir Nayfeh advanced that we can make a layer of nc-Si film on the surface of the cells to improve transition efficiency.The nanocrystalline silicon thin films were prepared on glass and (100) c-Si by ECR-PECVD using SiH4, H2, and O2 as source gases. In the preparation progress, different deposition parameters, such as substrate temperature, the flow rate of H2 and using H+ plasma etched in situ, high temperature fast annealing, are adopted to obtain various films of silicon serious. TEM, Raman and PL are applied to characterize the structure and physical properties of the films. The result showed that nanocrystalline silicon films of good quality in structure and optical properties are obtained by ECR-PECVD. The nature of the structure of nc-Si:H films is a two-phase composition framework, one of which is crystalline, another is amorphous. The Si crystalline, prefer to be in Si (111) phase and 6-10nm in size, are embedded in the amorphous matrix. The distribution of the crystalline is random, and the crystalline proportion in the films can reach 60～70%.The relation between deposition conditions and films'structure, properties is analyzed. A series of important conditions and original results are revealed, that is propitious to apply and investigate.