Microstructures and carrier transport behaviors of nanocrystalline silicon thin films

Hydrogenated amorphous Si thin films were prepared by plasma-enhanced chemical vapor deposition technique. As-deposited samples were thermally annealed above 800°C to obtain nanocrystalline Si and the microstructures and carrier transport behaviors were evaluated. It was found that the crystallization of amorphous silicon can be improved by increasing the annealing temperature. Temperature-dependent Hall measurements were performed and the Hall mobility of the thermally annealed sample is 0.86 cm²/V·s, which is one order magnitude larger than that of as-deposited amorphous Si film. The nanocrystalline Si films exhibit a thermally activated electrical transport above room temperature.