Properties of InN Grown by Remote Plasma Enhanced Chemical Vapour Deposition

We have investigated the properties of indium nitride (InN) grown at various temperatures on c-plane sapphire substrates using remote plasma enhanced chemical vapour deposition (RPECVD). The optical absorption spectra show a broad range of the apparent band-gap from 0.90 to 2.18 eV, depending on the growth temperature. These two extreme apparent band-gaps are similar to the controversial values of 0.7 and 1.9 eV quoted in the InN band-gap debate [1-3]. Along with optical absorption results, the influence of growth temperature on growth rate, and carrier concentration is discussed. The correlations between the carrier concentration, and shallowdonors (oxygen and hydrogen) in InN are also analysed.