Published online by Cambridge University Press: 26 February 2011
A new explanation is offered for the metastable changes caused by combined electric field and elevated temperature in properties of a-Si:H such as doping efficiency, solar-cell efficiency, and “structural relaxation.” This explanation is based on properties of the localized centers that are associated with the light-induced Staebler-Wronski effect and solar-cell degradation. The newfeature is recognition that the metastable state of these localized centers is more polarizable than the ground state, so that afield increases the energy difference between the two states. Then, when the temperature is high enough to permit transitions, the density of metastable defects decreases, producing the observed effects. This explanation is general in the sense that it does not depend on any atomic model of the centers involved.