Research On Preparation And Properties Of μc-SiGe/poly-SiGe/ZnO Thin Films For Solar Cell

In this thesis, based on the summary of research development of photovoltaic materials, we design and study Si1-xGex-based materials which used for solar cells, silicon-germanium monolayer and multilayer films were deposited on the quartz galss substrate by rf magnetron sputtering, and then films were annealed, the structure, surface images, composition, optical absorption properties and mechanical properties of films were studied by step profiler, XRD, Raman, SEM, EDS, UV-Vis and scratch test method.Firstly, the effects of sputtering pressures, input powers and substrate temperatures on the thickness, surface roughness, structure, surface images, composition, optical absorption properties and mechanical properties of silicon-germanium films were studied, respectively, results show that the deposition parameters for microcrystalline silicon-germanium films with atomic ratio of Si and Ge is about 1: 1, good optical absorption properties, surface quality, and mechanical properties is: sputtering pressure is 1.0Pa, input power is 100W, and substrate temperature is 400℃.Secondly, SiGe and SiGe/ZnO thin films were deposited by the optimized deposition parameters, then films were annealed, the effects of annealing temperature and the addition of ZnO layer on the structure and properties of SiGe films were studied. The results show that the structure of SiGe and SiGe/ZnO films transform from microcrystal to polycrystal at the annealing temperature is 600℃, with the increase of the annealing temperature, the crystallinity, optical absorption properties and mechanical properties improve, and the optical bandgap decreases; the addition of ZnO layer could improve the crystallinity and optical absorption properties of SiGe films, lower the optical bandgap and mechanical properties.At last, according to the different band structure of microcrystalline and polycrystalline SiGe films,μc-SiGe/poly-SiGe/ZnO multilayer films were designed and deposited. Results show that the addition of microcrystal layer could greatly improve the optical absorption properties of films, but lower the mechanical properties, the combination of the deposition of ZnO and microcrystalline layer could further improve the optical absorption properties of SiGe films.