Effects of rapid thermal annealing in InGaN/GaN quantum disk-in-GaN nanowire arrays

The effects of rapid thermal annealing on the structural and optical properties of InGaN/GaN quantum disk-innanowire heterostructure arrays have been investigated. Temperature-dependent and time-resolved photoluminescence measurements were complemented by x-ray photoemission spectroscopy. It was observed that annealing, in general, increased the non-radiative recombination rate in the InGaN quantum disk regions and consequently lowered the internal quantum efficiency and reduced the average carrier lifetime. These are due to an increase in the density of surface states associated with -O and -OH bonds in the disk region and possible enhancement of non-radiative recombination due to In segregation.