Water and oxygen environment induced surface cracks healing in solution processed gallium oxide thin films

Abstract

Solution based low temperature gallium oxide (Ga2O3) films with high quality is present need for large area deposition, cracks and other parameters resist the use of these films in applications. We have tried to develop good quality crack free films of Ga2O3. Deposition of Ga2O3 thin films by spin coating method and investigation of removal of surface cracks by adding secondary solvent (water) under oxygen environment. The as-synthesized film (without water and oxygen) shows cracks all over the surface. Deionized (DI) water and oxygen atmosphere act as efficient medium that alter surface energy of thin films while undergoing heat treatment. During the heat treatment of the thin films, addition of water forms interparticulate system between the molecules, yielding better evaporation balance and the oxygen environment helps to seize the rate of molecule evaporation which improves the surface uniformity of the thin film. A significant variation in the surface morphology of the films is observed using high-resolution scanning electron microscopy (SEM) and atomic force microscopy (AFM) images. X-ray diffraction (XRD) and Raman spectroscopy are used for the structural confirmation of the thin films. Increase in surface roughness is observed (from 0.28 nm to 0.98 nm) with increase in annealing temperature. Improvement in the crystalline feature results into augmented current density value. The developed crack-free films can be utilized for various electronics and optoelectronics application.