Free growth of one-dimensional β-Ga2O3 nanostructures including nanowires, nanobelts and nanosheets using a thermal evaporation method

Large-scale beta-Ga2O3 nanostructures (nanowires-NWs, nanobelts-NBs and nanosheets-NSs) were synthesized via thermal evaporation of GaN powder in an ambient argon atmosphere. The effect of the substrate type (Si, AlN-thin film/Si and ZnO-thin film/Si) on the growth of beta-Ga2O3 nanostructures was investigated. The morphology changes from NWs to NBs or NSs when the substrate changes from Si to AlN-thin film/Si or ZnO-thin film/Si, respectively. The size and dimensionality were the most influential parameters on the structure of the as-grown beta-Ga2O3. The as-grown nanostructures crystallize within the monoclinic crystal structure of the beta-Ga2O3 phase. The obtained nanostructures show intense blue red emission characterized by a broadband photoluminescence spectrum with peaks located at 430, 5000-525 and 688-700 nm. These emissions originate from the defect-related donor-acceptor pair recombination mechanism and depend on the nanostructure dimensionality and morphology. A vapor solid growth mechanism for the growth of various beta-Ga2O3 nanostructures was also proposed. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.