The dynamics of photoexcited carriers in microcrystalline silicon

Abstract

Dependences of the diffusion coefficient and the lifetime of photoexcited carriers in undoped microcrystalline silicon (μc-Si) on the volume fraction and the grain size were observed by a transient grating method and the dynamics of photexcited carriers is discussed. Under the condition of a constant grain size, the lifetime decreases with the increase of the volume fraction but the diffusion coefficient increases with the increase of the volume fraction for any fraction larger than 0.2. The dependence of the lifetime was explained well by a carrier recombination at grain boundary regions. The dependences of the diffusion coefficient and the dark conductivity were interpreted by a percolation process.