We present X-ray diffraction and Raman spectroscopy investigations of (InxGa1–x)2O3 thin films
and bulk-like ceramics in dependence of their composition. The thin films grown by pulsed laser
deposition have a continuous lateral composition spread allowing the determination of phonon
mode properties and lattice parameters with high sensitivity to the composition from a single 2-in.
wafer. In the regime of low indium concentration, the phonon energies depend linearly on the composition
and show a good agreement between both sample types. We determined the slopes of these
dependencies for eight different Raman modes. While the lattice parameters of the ceramics follow
Vegard’s rule, deviations are observed for the thin films. Further, we found indications of the highpressure
phase InGaO3 II in the thin films above a critical indium concentration, its value depending
on the type of substrate
