Temperature-dependent Raman scattering in cubic (InGa)2O3 thin films

We report measurements of Raman scattering of cubic In2O3 and (In0.83Ga0.17)2O3 films grown on sapphire substrates by pulsed laser deposition as a function of temperature (77-500 K). We analyze the temperature-dependent Raman shifts and linewidths of six Raman modes in In2O3 film and Ag(1) and Ag(2)/Tg(2) modes in (In0.83Ga0.17)2O3 film. The Raman shifts of phonon modes are found to vary linearly with temperature. The temperature coefficients for six Raman modes of In2O3 film are in the range of −0.014 and −0.006 cm−1/K, while temperature coefficients of Ag(1) and Ag(2)/Tg(2) modes in (In0.83Ga0.17)2O3 film are −0.017 and −0.024 cm−1/K, respectively. Through the aid of a model involving three- and four-phonon coupling, the effects of temperature on linewidths are clearly illustrated, which demonstrates that three-phonon process always dominates in the decay process for all the modes in both In2O3 and (In0.83Ga0.17)2O3 films. These basic properties are very important for improving the quality of In2O3 and (In0.83Ga0.17)2O3 films, which can be used as well and barrier layers in In2O3-based quantum well.