Study On Preparation, Microstructure And Properties Of Thin Films For Solar Cell On Glass Substrate

This paper aimed systematically at studying the sol-gel techniques and properties of transparent conducting oxide films and a-Si/poly-Si thin films for solar cell on the basis of the analysis of the progresses of building integrated photovoltaic (BIPV) materials. The effect of Sol-Gel techniques, magnetron sputtering conditions, annealing temperature and doped concentration of fluorin and antimony on TCO microstructure and electrical properties were systematical studied. Polycrystalline silicon films were fabricated by aluminum-induced crystallization. These films are prepared by plasma-enhanced chemical vapor deposition technology from hydrogen-diluted SiH₄. The effect of PECVD techniques and metal-induced crystallization on poly-Si thin films microstructure and optical properties were systematical studied. In this dissertation, some new and interesting results as following.(1) Fluorin-doped tin oxide thin films were fabricated on SiO₂ coated soda-lime glass by Sol-Gel dip coating method using SnCl₂·2H₂O and NH₄F as Precursors. Fluorin-doped tin oxide thin films were of uniformity with grain size 10nm.The sheet resistance was about reach 20～30Ω/(?), the visible transmission reached about 85%.(2) Antimony-doped tin oxide thin films were fabricated on SiO₂ coated soda-lime glass by the sol-gel dip coating method using metal salts SnCl₂·2H₂O and SbCl₃ as Precursors. The effect of heat-treatment temperature, antimony-doped level and coating thickness on the structure and composition of SnO₂ films. The optimum heat-treatment temperature is 773K, the tin oxide with antimony-doped suitable level is 5at%. The sheet resistance can reach 78Ω/(?), carrier concentration is 1.1×10²¹ cm^-3 with mobility 1.46cm²V^-1s^-1, and the visible transmission is about 75%.(3) Tin-doped Indium Oxide (ITO ) thin films have been deposited onto glass substrates by DC magnetron sputtering using ITO sintered target with 90 wt% In and 10 wt% Sn. The effect of oxygen partial pressures and substrate temperature on microstructure and electrical properties of ITO thin film has been investigated. The sheet resistance was about reach 20～30Ω/(?), the visible transmission reached about 85%, the crystallinity and grain size of ITO thin film has been improved with increasing oxygen partial pressures.Compared with fabrication techniques, Transparent conduction oxide thin films were obtained for solar cells with consistency and integration.(4) Polycrystalline silicon films were fabricated by aluminum-induced crystallization. These films are prepared by plasma-enhanced chemical vapor deposition technology from hydrogen-diluted SiH₄. The effect of thickness of aluminum films on the microstructure and morphology were investigated. The results were analyzed by XRD, RAMAN and SEM. The thickness of aluminum film was found to play a critical role in the extent of crystallization of a-Si thin film. a-Si films with thickness of 1μm aluminum film began to crystallize after annealing at 450℃for 20 min, a-Si films with thickness of 1μm aluminum film crystallize ferfectly after annealing at 500℃for 60 min,and the crystallinity of a-Si thin films was enhanced obviously with increment of thickness of aluminum films.(5) Fluorocarbon polymer films were prepared by radio-frequency magnetron sputtering of polytetrafluoroethylene (PTFE). The effect of argon and nitrogen gas pressure on surface composition, chemical structure, hydrophobic properties and mechanism were researched. This work may provide new insights and methods to prepare highly hydrophobic Fluorocarbon polymer films...