Temperature dependence of Ga2O3 micro/nanostructures via vapor phase growth

We have prepared the gallium oxide (Ga2O3) nanomaterials on Si (1 1 1) substrates by thermal evaporation of gallium in the ammonia atmosphere. The self-catalytic vapor–solid mechanism is used in explaining the formation mechanism. Scanning electron microscopy (SEM) revealed that the products contained many special structures, including spiral nanobelts, nanotrees and nanotubes locating in different temperature zones, respectively. The selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM) observations suggest that these as-synthesized products have a single-crystalline structure with a width ranging from 100 nm to several micrometers. Possible mechanism leading to the formation of Ga2O3 nanomaterials, especially the relation between temperature and some special structures is to be discussed in this paper. Photoluminescence spectrum under excitation at 396 nm showed a green emission, which is probably attributed to vacancies in Ga2O3.