Thermal annealing effects on the photoluminescence of InGaN/GaN quantum wells

Thermal annealing effects on the photoluminescence characteristics of InGaN /GaN quantum wells grown by metalorganic chemical vapor deposition were inv estigated. The emission peaks of the InGaN/GaN quantum wells are red-shifte d by conventional thermal annealing. The redshift behavior of the photolumi nescence peak energy is more prominent in samples grown at low temperatures . After a repetitive rapid thermal annealing, the red-shift behavior is obs erved even for InGaN/GaN quantum well samples grown at high temperatures. T he activation energy of localized excitons increases from 110 meV to 153 me V with increasing number of repetitive rapid thermal annealing cycles. Thes e abnormal red-shift behaviors in InGaN/GaN quantum wells due to thermal an nealing are understood by both dislocation-mediated indium interdiffusion a nd strain relaxation of pseudomorphically grown InGaN/GaN quantum wells.