Simultaneous Relaxation of Network and Defects in Silicon-Implanted a-Si:H

Abstract

ABSTRACTWe report extensive optical and electronic transport data on silicon-implanted a-Si:H, annealed in steps in the dark or with additional illumination. All measured properties relax gradually with increasing annealing temperature. The dark conductivity of the as-implanted film is dominated by hopping conduction via midgap defects. This channel is pinched off during the initial stages of annealing. The midgap defect density and the Urbach energy follow an annealing path that agrees qualitatively with the trajectory postulated by the equilibrium theory of the dangling-bond density. Therefore, the silicon network and the defect density equilibrate continuously during network relaxation.