Noise spectroscopy of local levels in semiconductors

A method for extracting the parameters of local levels from noise spectroscopic data for the case when the capture cross section of electrons sigma n depends on temperature exponentially, sigma n = sigma 0 exp(-E 1 /kT), has been suggested. For the limiting cases when the Fermi level E F lies significantly below (E F -E 0 >>kT) or above (E 0 -E F >>kT) the level E 0 , analytic expressions have been obtained to calculate sigma 0 , E 0 , E 1 and the level concentration N t . The results have been applied to noise-measurement data for GaAs samples with electron concentrations n 0 approximately 10 15 , 10 16 and 10 17 cm -3 . It has been shown that the technique proposed can be applied to a wide variety of experimental situations.