A method to determine bulk lifetime and diffusion coefficient of minority carriers; application to n-type LPE GaP

It is shown that the bulk lifetime and diffusion coefficient of minority carriers in semiconductor layers can accurately be determined from the dependence of near-band-edge exciton-luminescence decay on layer thickness. This method is applied to n-type LPE GaP using laser-pulse excitation. As we expected, large differences are observed between the actual bulk lifetime and the measured effective lifetime: the largest ratio amounts to a factor of 4. Bulk lifetimes as high as 5 μs and hole diffusion coefficients between 2.6 and 3.1 cm2/s are found at room temperature.