Mechanism of dispersive transport in hydrogenated amorphous silicon

Abstract

Temperature dependence of the electron mobility and the dispersion parameter in hydrogenated amorphous silicon films, deposited by glow-discharge decomposition and rf reactive sputtering methods, has been measured by means of time-of-flight technique. The results of the dispersion parameter are not consistent with the theoretical prediction which has been derived on the assumption of an exponential band tail. The temperature dependence of the electron mobility seems to be more likely to invoke the presence of traps located predominantly at about 0.2 eV below the conduction band. Several possibilities suitable to this situation are discussed.