Direct, functional relationship between structural and optical properties in titanium-incorporated gallium oxide nanocrystalline thin films

We present an approach to design Ga2O3-based materials with tunable optical properties. In the Ti-doped Ga2O3 model system, where the Ti content (x) was varied up to similar to 5 at. %, Ti induced significant effects on the structural and optical properties. Single-phase beta-Ga2O3 formation occurs for a lower Ti content (<= 1.5 at. %); however, composite-oxide (Ga2O3-TiO2) formation occurs for a higher Ti content. While band gap reduction (E-g similar to 0.9 eV) coupled with refractive index (n) enhancement occurs, indicating the electronic-structure modification, with Ti incorporation, the changes are dominant only in the Ga2O3-TiO2-composite. A direct, functional Ti(x)-Eg-n relationship was found, which suggests that tailoring the optical quality and performance of Ga-Ti-O is possible by tuning the Ti content and structure. Published by AIP Publishing.