Study Of Photovoltaic Effect Of Porous Silicon

In 1990, the observation of visible light emission from porous silicon (PS),and then realization of PS-based light emitting diodes gave a way to develop the silicon-based photo-electronics devices. But after a decade, there are many important problems those still exist now.In this thesis, the recent progress of PS was reviewed. And then the relationship between microstructure, minority carrier lifetime and photovoltaic effect of PS was systematically studied. The photovoltaic materials of PS-based are also investigated. Porous silicon was prepared by using oxidation etching on the p-type single crystal silicon, The results obtained by the surface photovoltage spectroscope (SPS) showed that the photovoltage of PS was increase than the photovoltage of single crystal silicon.Diffuse processes on the p-type single crystal silicon produced the p-n junction. Porous silicon was prepared by using oxidation etching on the surface of the single crystal with p-n junction. A quantum-sized thin film of TiO2 was deposited by reactive magnetron sputtering on the p-n junction. The results obtained by the surface photovoltage spectroscope (SPS) showed that the photovoltage of TiO2/n-Si/p-Si and n-PS/p-PS/Si increase than the photovoltage of n-Si/p-Si. In 300~600℃, the photovoltage of TiO2/n-Si/p-Si was enhancing with the rise of temperature, In 600~800℃, the photovoltage of TiO2/n-Si/p-Si was reducing with the rise of temperature.The effects of different ion-implantation in single crystal silicon and porous silicon on the photovoltaic characteristics are studied, and the morphology of ion implanted porous silicon and as-prepared porous silicon has been measured using scanning electron microscope (SEM). The results obtained by the surface photovoltage spectroscope (SPS) showed that the photovoltage of nitrogen implanted single crystal silicon was increased nearly three times than the photovoltage of single crystal silicon, and the photovoltage of argon implanted single crystal silicon was increased nearly seven times than the photovoltage of single crystal silicon. The photovoltage of argon implanted porous silicon and nitrogen implanted porous silicon was increased a lot beyond the photovoltage of PS.