Abstract The band structures of wurtzite GaN($\alpha$-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 $\alpha$-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 ($\varepsilon$2 ($\omega$)) are evaluated to he in the regions - 10.0 - 12 eV and (1.0 - 10.0 eV, respectively. There are mainly three peaks at 6,4, 7,5, 8.4 eV, dominating the ($\varepsilon$2 ($\omega$)) spectrum. The two components of the ($\varepsilon$2 ($\omega$)) (i. e. $\varepsilon$2xy($\omega$) and $\varepsilon$2z($\omega$) ) are also calculated; and the real prat of dielectric function, reflectivity, absorption coefficient, and refractive index are all studied.
Received: 19 June 1996
Revised: 16 October 1996
Accepted manuscript online:
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