Electronic structure of amorphous semiconductors

The effect of light soaking and thermal quenching on the electronic structure of hydrogenated amorphous silicon (a-Si:H) and chalcogenide glasses was studied. It was found that lithium doped a-Si:H shows both light and thermal induced changes in electronic transport properties. In contrast, chalcogenides do not show any effect of thermal quenching, although they exhibit changes upon light soaking. By analysing the conductivity and thermopower data we have concluded that the light soaking increases the potential fluctuations present in lithium doped a-Si:H, whereas quenching does not change them. A model qualitatively explaining these effects is presented.