AB-INITIO CALCULATION OF ELECTRONIC-PROPERTIES OF GA1-XALXN ALLOYS

The electronic properties of the wide-band-gap semiconducting ordered Ga1-xAlxN alloys (for x = 0.0, 0.25, 0.50, 0.75 and 1.0) and the rando m alloys have been investigated by using a full-potential self-consist ent linear muffin tin orbital (LMTO) method. The calculated direct ban d gap for random distribution of cation nearest-neighbour tetrahedral clusters in the Ga1-xAlxN alloys for any arbitrary concentration x is seen to show a quite linear variation in agreement with the experiment . On the other hand, the indirect band gap remains invariant. We obser ve a direct to indirect band gap crossover at x = 0.59. The band gap b owing is seen to be very small.