Influence of variation of lithium concentration on metastabilities in a-Si:H(Li)

Abstract Effects of rapid cooling (FQ) from high temperature and light soaking (LS) at room temperature using heat filtered white light on transport properties of lithium doped a-Si:H(Li) have been studied for varying lithium (Li) concentrations while keeping the hydrogen content fixed. This study was possible as Li was introduced by thermal diffusion after a-Si:H films were prepared by glow discharge technique. We find that the equilibrium temperature T E is lower for a-Si:H(Li) with larger lithium concentration. The isothermal relaxation studies in the metastable FQ and LS states show that for a given state, relaxation is always slower for less doped a-Si:H(Li). These results can be understood in terms of diffusion of hydrogen, if we assume that the presence of lithium increases the diffusion coefficient of hydrogen in a-Si:H.