Phase stabilization and phonon properties of single crystalline rhombohedral indium oxide

We report on the phase stabilization of rhombohedral (rh-) In2O3 films on sapphire substrate deposited by metal organic chemical vapor deposition. With the help of a high-temperature nucleation layer and evolutionary structural selection of rhombohedral phase during the growth process, stable epitaxial growth of single crystalline rh-In2O3 is achieved. The mechanism of phase selective epitaxial growth is studied by means of high-resolution X-ray diffraction and transmission electron microscopy measurements. Furthermore, Raman spectroscopy measurements are carried out to investigate the phonon properties of rh-In2O3, Raman-active phonon modes of rh-In2O3 are first identified.