Investigation of optical nonlinearities and carrier dynamics in in-rich InGaN alloys

We present experimental studies of nonequilibrium carrier dynamics in InGaN alloys with 70-90% content of In by using picosecond transient grating technique. The observed faster recombination rate in alloys with higher Ga content and formation of a thermal grating via a lattice heating, being more pronounced for layers with larger band gap, indicated that the main reason of the heating is not the excess energy of photons, but the defect density which increases with Ca content. A gradual decrease in carrier lifetime with excitation or with increasing temperature in 50-300 K range point out the role of potential barriers in carrier recombination.