Density of states and temperature dependence of the exponent in the light-intensity behavior ofa-Si:H photoconductivity

We report experimental measurements concerning the temperature dependence of the {γ} exponent in the light-intensity behavior of the photoconductivity of hydrogenated amorphous silicon (a-Si:H). We find that good agreement between experimental results and numerical calculations is achieved if a peak in the density of states (DOS) above the dark Fermi level is assumed. Other forms suggested for the DOS in a-Si:H are surveyed for comparison. Finally, we propose a simple relation between DOS and measurable quantities and make estimates for some physical parameters for this material.