Determination of the drift mobility in high-conductivity amorphous silicon

A new technique for measuring the drift mobility in semiconductors is proposed. This method consists in measuring the current transient in a Schottky-barrier device during a reverse bias voltage pulse. Measurements on a-Si:H doped with 0.2% phosphorous show a temperature activated mobility. The activation energy is 0.13 eV and the drift mobility is about 6.5×10−2 cm2/V sec at room temperature. This technique is particularly applicable to material in which the dielectric relaxation time is shorter than the carrier transit time, precluding time-of-flight measurements.