Light-induced changes of the 1/f noise in hydrogenated amorphous silicon

The 1/f-noise power spectra of coplanar current fluctuations in n-type doped hydrogenated amorphous silicon (a-Si:H) are measured before and after light-induced metastable defects (the Staebler-Wronski effect) are created. The noise spectral density for the annealed state is strongly non-Gaussian, with large correlations of the noise power between differing octaves. Upon illumination the noise becomes Gaussian and the correlation coefficients of the noise power decrease, which is consistent with an increase in the disorder at the mobility edge in a-Si:H in the light-soaked state.