Effect of annealing on β-Ga2O3 film grown by pulsed laser deposition technique

Abstract

• β-Ga 2 O 3 films were grown on sapphire substrate (0 0 0 1) by pulsed laser deposition. • X-ray diffraction, Secondary ion mass spectrometry and UV–Visible spectroscopy. • As grown films were oriented [ 4 0 1 ¯ ] and transparent in the UV and visible region. • Structure and band gap as a function of temperature, beam energy and annealing. • Al diffusion from the substrate after annealing results in increase of band gap. Oriented [ 4 0 1 ¯ ] β-Ga 2 O 3 films were grown on sapphire substrate (0 0 0 1) 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 β-Ga 2 O 3 films by Al diffusion from the sapphire substrate the films were annealed for 24 h 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 diffusion of Al was also confirmed using secondary ion mass spectrometry (SIMS) depth profiling. The annealed films showed high transparency in the deep UV region of the spectrum.