Catalyst-modified Vapor-Liquid-Solid (VLS) Growth of Single Crystalline β-Gallium Oxide (Ga2O3) Thin Film on Si-Substrate

Abstract: In the current work, a single crystalline β-Gallium Oxide (Ga2O3) thin film (∼15 nm) is grown on Si-substrate by employing catalyst-modified vapor-liquid-solid (VLS) method. The FESEM and AFM images indicate the formation of a continuous film with small surface roughness. XRD measurement confirms the formation of a highly crystalline >-plane of β-phase of Ga2O3. The chemical states and optical properties of such films are analyzed by X-ray photoelectron spectroscopy (XPS) and Spectroscopic ellipsometry (SE). The energy bandgap, refractive index and extinction coefficient of the grown β-Ga2O3 film are obtained to be 4.78 eV, 1.84 and 0.10, respectively. The vacancies/defect states are studied from Photoluminescence (PL) spectra where the major PL-peaks corroborate with the transitional energy values obtained from SE measurement. Therefore, the study suggests that the VLS method, amongst the state-of-the-art growth techniques, is capable of growing high-quality single crystalline β-Ga2O3 thin film in a relatively simple and cost-effective approach.