Electronic Structures of Wurtzite GaN, InN and Their Alloy Ga1-xInxN Calculated by the Tight-Binding Method

The semi-empirical tight-binding method is used to investigate band structures of wurtzite III-V nitride semiconductors. The tight-binding band structures of GaN and InN are first obtained by fitting the data to experiments and more accurate calculations. To obtain better description of the band structures, second-nearest-neighbor s and p state interactions are included and Ga 3d and In 4d electrons are treated as band states. Then, the band structure of the alloy Ga1- x In x N is predicted based on the obtained tight-binding parameters and a pseudobinary alloy model. The predicted alloy band gaps are in good agreement with experimental ones. The electron effective masses of the alloy are also presented. The effects of the second-nearest-neighbor interactions and nearest-neighbor s-d and p-d state interactions on the band structures are discussed in detail.