Thermal annealing effect in GaInNAs thin films estimated by fluorescence X-ray absorption fine structure spectroscopy

The radiative efficiency of dilute nitride GaInNAs alloys is improved by thermal annealing. However, the band gap of these alloys is found to significantly blueshift. The structural changes of these alloys occur during thermal annealing. In this study, we studied the local atomic configuration around In atoms using fluorescence X-ray absorption fine structure spectroscopy. By comparing the radial distribution functions of as-grown and annealed GaInNAs thin films, it was found that the number of In atoms surrounding N atoms increases after thermal annealing.