The Effects Of Thermal Annealing Treatments On Ingan/Gan Quantum Well Structures

Thermal annealing effects on the photoluminescence characteristics of InGaN/GaN quantum wells grown by metalorganic chemical vapor deposition were investigated. The emission peaks of InGaN/GaN quantum wells are red-shifted by thermal annealing. The red-shift behavior of photoluminescence peak energy is more prominent in samples grown at low temperatures. The red-shift behavior even for high temperature grown InGaN/GaN quantum well samples is observed after a repetitive rapid thermal annealing. The activation energy of localized excitons increases from 110 meV to 153 meV with increasing the number of repetitive rapid thermal annealing cycle. These abnormal red-shift behaviors in InGaN/GaN quantum wells are understood by both dislocation mediated indium interdiffusion and strain relaxation of pseudomorphically grown InGaN/GaN quantum wells.