The mobility activation energy of hydrogenated amorphous silicon

Recent experimental results indicate that the density of conduction band tail states g(E) in a-Si: H below the mobility edge E_cinitially decreases linearly with increasing depth E_c—E and subsequently, below an energy E_cdecreases at an exponential rate. In this Letter we examine the temperature range in which such a density of states may be expected to lead to a mobility activation energy E_µclose to E_c-E₀and how E_µwill behave at other temperatures.