Nonlinear 1/f noise in amorphous silicon

Measurements of coplanar current fluctuations in n-type hydrogenated amorphous silicon (a-Si:H) find that the spectral density of the noise accurately obeys a 1/f frequency dependence for frequency f in the range 1, 103 Hz over a temperature range 300T, 450 K. The noise power density displays a power-law dependence on the dc current, where the power-law exponent b increases with temperature from b1 at 350 K to 2.5 at 450 K. These results are discussed in terms of models for noise in composite and inhomogeneous materials.