Fig. 1

The growth and characterization of ZnO:Ga single crystal. a Growth diagram of ZnO:Ga single crystal via hydrothermal method. b Single crystal rock curve of ZnO:Ga single crystal. The illustration is the optical photograph of as-grown large-size ZnO:Ga single crystal. c Ultraviolet photoluminescence spectrum of 2-inch ZnO:Ga wafer. Inset is photograph of the ZnO:Ga wafer. d High-resolution transmission electron microscopy (HRTEM) image of the ZnO:Ga single crystal. The selected-area diffraction pattern shows distinct spots with hexagonal shape, indicating a high quality of the ZnO:Ga single crystal. e and (f) show the enlarged atoms pattern, corresponding to the b and c plane of crystal respectively. The right diagrams are the crystal structure viewed along b and c plane. The red and gray spheres represent oxygen and zinc atoms, respectively