Impact of electron injection on carrier transport and recombination in unintentionally doped GaN

The impact of electron injection on minority carrier (hole) diffusion length and lifetime at variable temperatures was studied using electron beam-induced current, continuous, and time-resolved cathodoluminescence techniques. The hole diffusion length increased from 306 nm to 347 nm with an electron injection charge density up to 117.5 nC/μm3, corresponding to the lifetime changing from 77 ps to 101 ps. Elongation of the diffusion length was attributed to the increase in the non-equilibrium carrier lifetime, which was determined using ultrafast time-resolved cathodoluminescence and related to non-equilibrium carrier trapping on gallium vacancy levels in the GaN forbidden gap.