Raman Spectroscopy as an Effective Tool for Assessment of Structural Quality and Polymorphism of Gallium Oxide (Ga2O3) Thin Films.

Abstract

Raman spectroscopy, a versatile and nondestructive technique, was employed to develop a methodology for gallium oxide (Ga₂O₃) phase detection and identification. This methodology combines experimental results with a comprehensive literature survey. The established Raman approach offers a powerful tool for nondestructively assessing phase purity and detecting secondary phases in Ga₂O₃ thin films. X-ray diffraction was used for comparison, highlighting the complementary information that these techniques may provide for Ga₂O₃ characterization. Few case studies are included to demonstrate the usefulness of the proposed spectroscopic approach, namely the impact of deposition conditions such as metal-organic vapor-phase epitaxy and pulsed electron deposition (PED), and extrinsic elements provided during growth (Sn in the case of PED) on Ga₂O₃ polymorphism. In conclusion, it is shown that Raman spectroscopy offers a quick, reliable, and nondestructive high-resolution approach for Ga₂O₃ thin film characterization, especially concerning phase detection and crystalline quality.