Reduced light-induced degradation in a-Si:H: The role of network nanostructure

In this work, we report our recent observations on strong reduction in Staebler-Wronski (SWE) effect in device quality a-Si:H that has been post-deposition annealed up to 400C, and make a connection between these observations and changes in a-Si:H network nanostructure and H bonding, both from our own FTIR and NMR measurements and from the SAXS and NMR literature. The results suggest that it is the smallest (atomic size) voids in a-Si:H that are most likely responsible for the Staebler-Wronski effect. Thermal treatments up to 400C lead to coalescence and restructuring of these voids leading to reduction of SWE.