Exciton localization in group-III nitride quantum wells

Exciton density of states broadened by compositional disorder in the group- Ill nitride quantum well is calculated. The excitonic photoluminescence lin ewidth is estimated and related to the material parameters of the alloy for two limiting cases of two-dimensional (2D) and three dimensional excitons in the quantum well. It is shown that the effect of the compositional fluct uations depends on dimensionality of the exciton: the 2D excitons are more sensitive to the inhomogeneities than 3D ones. The broad near-band-gap ener gy states distribution for quasi-two-dimensional excitons is consistent wit h the experimental evidence of the spontaneous and stimulated emissions fro m excitonic states localized on compositional fluctuations. [S0163-1829(99) 04015-1].