Structural and optical properties of ZnO micro-spheres and cages by oxidation of metallic Zn powder

Ultra violet sensors based on nanostructured ZnO spheres in network of nanowires: a novel approach

“…The formation of different shapes of nanostructures depends largely on temperature, pressure, heating/cooling rates and the saturation of reactive elements in the gaseous phase during the reaction. There have been reports on fabrication of complex ZnO structures with morphology like mushroom [22], spheres [23], ellipsoids, flowers and propellers [24]. Luo et al [25] have reported the fabrication of UV photodiode by forming a heterojunction of n-ZnO nanowires of diameter (70-120 nm) with p-type Si.…”

Zinc oxide nanostructures and their applications

“…Although not illustrated, Raman scattering analysis showed a characteristic ZnO wurtzite hexagonal peak at 436.9 cm −1 in case of Si(100) substrate, while at 437 cm −1 in case of steel alloy substrate. The roomtemperature PL spectra in both the cases showed a broad band in the visible region with suppressed and short UV emission, indicating that these structures had some structural defects such as zinc interstitials and oxygen vacancies [45]. Polyhedral cages and shells were formed on alumina substrates via the solid-vapor deposition process using the commercial ZnO, SnO 2 and graphite powders at 1,100 o C [46].…”

“…Fig. 6 shows the growth of ZnO nanospheres and micro-sized hollow spheres/cages (top) [45] and polyhedral cages of ZnO (bottom) [130]. The ZnO nanospheres and micro-sized hollow spheres/ cages were synthesized on Si(100) and steel alloy substrates in a high density via the thermal evaporation using different zinc precursors, i.e., ZnCl 2 and metallic zinc powder in the presence of oxygen.…”

“…(Top) SEM images of ZnO microcages/spheres grown onto the Si(100) (a) and steel alloy substrates(b), respectively synthesized by thermal evaporation of metallic zinc powders[45]. (Bottom) SEM images of single-crystalline polyhedral cages and shells of ZnO[46].…”

Large-quantity synthesis of ZnO hollow objects by thermal evaporation: Growth mechanism, structural and optical properties

“…In this endeavor, recently scientists are inclined to pay much attention on the fabrication of materials with specific morphologies because of the expectation of novel properties. For the use of specific applications, so far a variety of ZnO nano-and microstructures are already fabricated and reported in the literature which include ZnO rods and wires [5][6][7][8][9][10][11][12][13][14], tubes [15,16], belts [17], propeller [18], stars [19], helixes, springs and rings [20], nanosheet networks and hexagonal disks [21], nanobridges and nails [22], columns [23], hierarchical structures [24], flower-shaped structures [25], nano and micro hollow shells, cages and spheres [26][27][28][29][30], and so on. Among these diverse morphologies of ZnO, the nano-and microspheres with hollow interiors/cages, because of their lower densities and higher surface areas, are presenting an appealing structural design as compared to their bulk materials.…”