Temperature-Dependent Anisotropic Refractive Index in β-GaO: Application in Interferometric Thermometers.

An accurate knowledge of the optical properties of β-GaO is key to developing the full potential of this oxide for photonics applications. In particular, the dependence of these properties on temperature is still being studied. Optical micro- and nanocavities are promising for a wide range of applications.

Effect of extended defects on photoluminescence of gallium oxide and aluminum gallium oxide epitaxial films.

In this work, a systematic photoluminescence (PL) study on three series of gallium oxide/aluminum gallium oxide films and bulk single crystals is performed including comparing doping, epitaxial substrates, and aluminum concentration. It is observed that blue/green emission intensity strongly correlates with extended structural defects rather than the point defects frequently assumed. Bulk crystals or Si-doped films homoepitaxially grown on (010) β-GaO yield an intense dominant UV emission, while samples with extended structural defects, such as gallium oxide films grown on either (-201) β-GaO or sapphire, as well as thick aluminum gallium oxide films grown on either (010) β-GaO or sapphire, all show a very broad PL spectrum with intense dominant blue/green emission.