Raman Studies on Metal-Assistant Laser-Induced Nanocrystalline Silicon Thin Films

摘要

In this paper, we put forward an alternative route so called metal-assistant laser-induced crystallization to prepare nanocrystalline silicon thin films. Both the amorphous silicon and aluminium layers were deposited by magnetron sputtering system at low temperature without any hazardous gases. Microstructure of the films is investigated using Raman spectra, and the effects of aluminium content and laser power density on crystallization behavior of the silicon films are studied intensively. It is found that by applying a little amount of aluminium, not only the laser energy threshold of crystallization is lowered but also the crystalline volume fraction is improved significantly. The film containing 86% silicon nanocrystals with mean grain size of 4.9 nm is achieved. We attribute the origin of enhanced crystallization to the more silicon nuclei. Based on our findings, the metal-assistant laser-induced crystallization will hopefully provide a safe, effective and low cost alternative method for the fabrication of nanocrystalline silicon thin films.