Apparent band-gap shift in InN films grown by remote-plasma-enhanced CVD

The properties of indium nitride grown at various temperatures on c-plane sapphire and glass substrates, using remote plasma-enhanced chemical vapour deposition, have been investigated. The optical absorption spectra show a broad range of apparent band-gap values from approximately 2.3–0.9 eV, depending on the growth temperature. The influence of growth temperature on crystallinity, level of impurity incorporation, stoichiometry, and lattice distortion are analysed. The possible causes of the apparent band-gap shift in indium nitride are discussed.