Influence of Sm3+ doped β-Ga2O3 thin films on structural, optical, and photoluminescence properties

The pure and Sm-doped (1, 3, and 5 at%) beta-Ga2O3 thin films were deposited on a glass substrate using the sol-gel spin coating method and investigated the structural, morphological, and optical properties. The XRD studies revealed that all deposited thin films exhibited polycrystalline monoclinic beta-phase structure. The crystalline quality was greatly improved with the Sm-doping. The SEM-EDS, XPS, and Raman spectroscopy measurements confirmed the Sm element was successfully incorporated into the beta-Ga2O3 host lattice. The photoluminescence spectra showed a wide blue band region centered at 439 nm in all the films. The average optical transmittance was above 73% in the visible spectra for all deposited films. The optical band gap energy (E-g) decreased from 4.83 eV for pure beta-Ga2O3) film to 4.68 eV for 5 at% Sm-doped beta-Ga2O3 films.