The lattice dynamical properties of the corundum-like a-phase of Ga 2 O 3 are investigated by means of Raman scattering experiments and ab-initio calculations. A high-quality, single-crystal thick epilayer was grown on sapphire by the mist-chemical vapor deposition method. The phonon frequencies at the Brillouin zone center of all the Raman-active modes are determined by polarized Raman scattering measurements on an a-Ga 2 O 3 single crystal. By performing backscattering measurements from (0001) and ð10 10Þ faces, all Raman active modes are unambiguously identified. Density functional perturbation theory calculations were carried out to determine the symmetry and the frequency of the a-Ga 2 O 3 lattice modes. We find a good agreement between the theoretical predictions and the Raman spectra. The relative intensity of the different modes and their polarizability are discussed. The Raman spectrum is dominated by a narrow A 1g peak which indicates the high crystalline quality of the layers grown by the mist chemical vapor deposition method. V C 2015 AIP Publishing LLC. [http://dx

Cathodoluminescence (CL) spectra were measured from polycrystalline Ga–In–O (GIO) films prepared by the molecular precursor method (MPM). Bandgap-energy (E g) and conductivity were successfully controlled by changing in the mixing ratio of the Ga and In precursor solutions. Although none of the films exhibited a near-band-edge emission, their CL emissions exhibited energy shifts by reflecting changes in E g and ligand field in the GIO alloys. The results indicate a practical use of MPM-grown GIO films for deep ultraviolet optoelectronic devices.

High-temperature oxidation behavior of Ni-20Cr alloys with small amounts of rare earth elements (Y, Lu) was studied in oxygen for 18ks at 1473K, by mass gain measurements, observation of surface appearance, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The mass gains of the Ni-20Cr alloys with rare earth elements decreased with increasing Y and Lu up to 0.5%. The outermost continuous scale on Ni-20Cr alloy consists of NiO which is a planar morphology. On the other hand, the scale on Ni-20Cr-0.5Y (Lu) alloys consists of Cr 2 O 3 which is a fine granular morphology.