Effect of Reduction in Impurity Content for a-Si:H Films

Abstract

A-Si:H films with various impurity contents were prepared by three kinds of glow discharge decomposition systems. The impurity content for films prepared by these systems was determined by SIMS, and the dark conductivity and the density of charged dangling bonds were also measured. The following results were obtained: the dark conductivity σ_d, the activation energy E _a and the density of charged dangling bonds are closely correlated with the N and/or O impurity content. These results suggest that the Fermi level and the charged dangling bond density in a-Si:H are largely affected by the presence of the impurity-defect pair such as N₄ ⁺+Si₃ ^- and/or O₃ ⁺+Si₃ ^-.