Minority carrier lifetime variations associated with misfit dislocation networks in heteroepitaxial GaInP

Variations in minority carrier transport properties associated with networks of misfit dislocations have been measured using a unique optical technique in p-type GaInP grown on Ge. The diffusion length L of minority carriers has been measured with a spatial resolution of 0.4 µm in regions showing alternating light and dark luminescence bands. Periodic variations of ±4% from a mean diffusion length of 3.9 µm were measured and found to be anti-correlated to intensity fluctuations. A model based on the coupling between luminescence intensity and minority carrier lifetime allows for the extraction of spatial variation of both radiative and non-radiative lifetimes. For this high quality material, with relatively low concentrations of non-radiative recombination centers, the results indicate variations in radiative recombination lifetime associated with dopant fluctuations.