Effect of epitaxial growth rate on morphological, structural and optical properties of β-Ga2O3 films prepared by MOCVD

Abstract

This study investigated the effects of growth rate on the properties of monoclinic β-Ga2O3 films grown on SrTiO3 (100) substrates by Metal-organic Chemical Vapor Deposition. The β-Ga2O3 films deposited at the low rate exhibited monocrystalline structure, for which the structural analyses identified the epitaxial relationship of β-Ga2O3 (100) // SrTiO3 (100) with β-Ga2O3 〈001〉 // SrTiO3 〈011〉. In the case of the same film thickness, as the growth rate increased from 2.1 to 10.1 nm•min−1, the surface root-mean-square roughness of the β-Ga2O3 film increased from 6.96 to 8.41 nm, and the crystalline quality decreased obviously. The prepared β-Ga2O3 films exhibited a band gap of about 4.9 eV, and the refractive index in 450–800 nm wavelength range was 2.25–2.02. Moreover, the transmittance of all samples in the visible region was around 75%.