Conductance-noise power fluctuations in hydrogenated amorphous silicon

The power spectra of the 1/f noise in n-type-doped hydrogenated amorphous silicon (a-Si:H) are themselves time dependent. The noise power changes both in magnitude and as a function of frequency, reflecting a modulation of the properties of the fluctuators responsible for the current noise. Slow variations of the noise are strongly correlated over a broad range of frequencies. Spectral analysis of these noise power fluctuations, termed second spectra, also shows an approximate 1/f spectral slope, that is, the 1/f noise has 1/f noise. These results indicate that highly cooperative interactions exist between the fluctuators.