Nonlinear 1/fnoise 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<f<${10}^3$ Hz over a temperature range 300≤T≤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 b∼1 at 350 K to ∼2.5 at 450 K. These results are discussed in terms of models for noise in composite and inhomogeneous materials.