Study of the electronic properties of hydrogenated amorphous silicon films by femtosecond spectroscopy

Experimental results on the electron relaxation time and diffusion coefficient in hydrogenated amorphous silicon films that exhibit intrinsic and electronic conductivity at room temperature are reported. It is found that, for these two types of films, the relaxation times are 1 ns and 465 ps and the diffusion coefficients are 0.54 and 0.83 cm$^2$ s$^{-1}$. It is established that, as the pulse intensity is increased, the decay time of the induced-grating signal shortens.