Carrier recombination processes in In-polar n-InN in regions of low residual electron density

Photoluminescence (PL) spectra of In-polar n-type InN films with different dislocation and residual electron densities are investigated in the temperature range 15-300 K. The dependence of PL intensity on temperature is analyzed by using a model function that is based on rate equations for photoexcited hole density. By considering the relation between the dislocation densities estimated from the widths of the peaks of x-ray omega-rocking curves and the parameters obtained from the rate equations, two kinds of nonradiative carrier recombination processes are identified. One process is independent of threading dislocations and is thermally activated, while the other takes place in the vicinity of edge-type dislocations and requires no activation energy.