Recombination dynamics of localized excitons in Al1-xInxN epitaxial films on GaN templates grown by metalorganic vapor phase epitaxy

Recombination dynamics of excitons in nearly strain-free Al1-xInxN alloys on the GaN template were studied. Their band-gap energy showed a nonlinear dependence on the InN molar fraction x, and the bowing parameter was determined to be approximately -3.1 eV. Most of the alloys exhibited an extremely diffused band-edge, and consequently exhibited huge Stokes-type shifts up to 1-2 eV and full width at half maximum of the luminescence peaks up to 0.5 eV. The results suggested enhanced material inhomogeneity in AlInN compared to InGaN alloys. Since the time-resolved photoluminescence signal showed a pronounced stretched exponential decay, the spontaneous emission was assigned as being due to the radiative recombination of excitons localized in disordered quantum nanostructures. The integrated PL intensity at 300 K was as strong as 29% of that at low temperature, showing a potential use of AlInN alloys as infrared-to-UV light emitters. (C) 2003 American Institute of Physics.