Blueshift of In0.2Ga0.8N/GaN single quantum well band gap energy by rapid thermal annealing

Up to 15 nm blueshift in the low-temperature photoluminescence (LT-PL) peak wavelength of Si-doped In0.2Ga0.8N/GaN single quantum well (SQW) is report ed after rapid thermal annealing in atmospheric N-2 ambient at temperatures below 1000 degrees C. We found that the thermal annealing not only blueshi fts the LT-PL peak wavelength but it also improves the optical properties i n terms of an increase in LT-PL peak intensity and a reduction in the spect rum width. Under the same thermal annealing conditions, however, a dielectr ic encapsulant layer (a spin-on silica layer) suppresses the blueshift of t he LT-PL peak wavelength of the In0.2Ga0.8N/GaN QW. The effect of the therm al annealing temperature and time on the blueshift of the LT-PL peak wavele ngth is also reported. The possible mechanism responsible for the thermal a nnealing effect on the band gap energy of the In0.2Ga0.8N/GaN SQW is discus sed. (C) 1999 American Vacuum Society. [S0734-211X(99)06604-4].