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.