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 < f < 10(3) Hz over a temperature range 300 less-than-or-equal-to T less-than-or-equal-to 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 approximately 1 at 350 K to approximately 2.5 at 450 K. These results are discussed in terms of models for noise in composite and inhomogeneous materials.