Light Induced Changes in the Non-Gaussian Noise Statistics in Doped Hydrogenated Amorphous Silicon

Abstract

The power spectrum of coplanar current fluctuations in n-type doped hydrogenated amorphous silicon (a-Si:H) has been measured before and after metastable defect creation by light soaking. The average magnitude and spectral slope of the 1/f noise are not affected by illumination, however significant changes in the higher order statistics are observed. Associated with the decrease of conductivity upon light soaking (the Staebler-Wronski effect), there is a decrease in the correlation of the noise power which characterize the non-Gaussian noise in the annealed state. These changes in the noise statistics are reversible by annealing. The light-induced changes in the non-Gaussian statistics provide experimental support for models of light induced defect creation which involve long-ranged and many body interactions.