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(-E₁/kT), has been suggested. For the limiting cases when the Fermi level E_F lies significantly below (E_F-E₀>>kT) or above (E₀-E_F>>kT) the level E₀, analytic expressions have been obtained to calculate sigma ₀, E₀, E₁ and the level concentration N_t. The results have been applied to noise-measurement data for GaAs samples with electron concentrations n₀ approximately 10¹⁵, 10¹⁶ and 10¹⁷ cm^-3. It has been shown that the technique proposed can be applied to a wide variety of experimental situations.