Amorphous silicon as hydrogen glass

The hydrogen in hydrogenated amorphous silicon (a-Si:H) makes it behave like a hydrogen glass. Above a temperature T-E, which is analogous to the glass transition temperature, the hydrogen is able to move more freely than below T-E. This motion of hydrogen is believed to be responsible for the observed thermal and light induced metastabilities in a-Si:H. However, the changes in the microstructure of the bonded hydrogen upon thermal quenching are found to influence the electronic properties of a-Si:H, in a manner, which is different from light soaking. Our studies suggest that the light soaking changes the potential fluctuations in lithium doped a-Si:H, whereas the thermal quenching does not.