ELECTRONIC AND OPTICAL PROPERTIES OF WURTZITE GaN:——A THEORETICAL APPROACH

The band structures of wurtzite GaN(α-GaN) are studied using the nearest and second-nearest neighbour semi-empirical tight-hinding method in sp3 s* model. The calculated direct fundamental gap of α-GaN is 3.45 eV, which is in good agreement with the experimental data. The density of states and the imaginary pert of dielectric function (ε2 (ω)) are evaluated to he in the regions - 10.0 - 12 eV and (1.0 - 10.0 eV, respectively. There are mainly three peaks at 6,4, 7,5, 8.4 eV, dominating the ε2(ω) spectrum. The two components of the ε2(ω) (i. e. ε2xy(ω) and ε2z(ω) ) are also calculated; and the real prat of dielectric function, reflectivity, absorption coefficient, and refractive index are all studied.