The study of composition non-uniformity in ternary MgxZn1-xO thin films

We report on the growth of single cubic-phase MgZnO thin films by reactive electron beam evaporation on sapphire substrates. A detailed theoretical procedure has been employed to analyse the transmission profile for information on composition non-uniformity, in addition to the exact determination of the band gap energy. The study of composition non-uniformity has been further extended to both the typically reported hexagonal and cubic MgZnO thin films. It is found that the composition non-uniformity strongly depends on the Mg content, which can be well explained by the ZnO-MgO phase diagram.