Structural and Optical Characterization of β-Ga2O3 Thin Films Grown by Pulsed Laser Deposition

Polycrystalline beta-Ga2O3 thin films were grown on sapphire substrate (0001) by pulsed laser deposition (PLD) technique. The crystalline structure and optical band gap were studied as a function of growth temperature, laser beam energy, annealing temperature and time. To tailor the band gap of beta-Ga2O3 thin films by Al diffusion from the sapphire substrate the films were annealed for 24 hrs at different temperatures. The amount of Al diffusion was different for different temperatures of annealing which resulted in the increase of band gap as well as the shift of diffraction peaks to higher angles with increasing temperature. The annealed films showed high transparency in the deep UV region of the spectrum.