Energy band‐gap bowing parameter in an AlxGa1−xN alloy

摘要

Optical measurements are performed near the fundamental absorption edge for single‐crystal AlxGa1−xN epitaxial layers in the composition range of 0≤x≤0.4. The dependence of the energy band gap on composition is found to deviate downwards from linearity, the bowing parameter beingb=1.0±0.3 eV. The origin of the large bowing is discussed in terms of the pseudopotential of Al and Ga based on the pseudopotential of the Heine–Abarenkov type. With increasingxthe absorption edges broaden, which is attributed to the increase of the compositional nonuniformity.