Band gap bowing parameter of In1−xAlxN

We report a band gap bowing parameter for In1−xAlxN of 4.7 eV from a study of high quality and homogenous samples with x=0.017–0.60. Optical absorption data were modeled to extract the band gaps in order to consider the complications of the band structure of In-rich InAlN, including the Burstein–Moss shift, nonparabolic conduction band, and broadening of the absorption edge. The alloy compositions were accurately determined using Rutherford backscattering spectrometry and the sample quality was evaluated using x-ray diffraction and channeling-RBS.