“…Among the functional semiconductors, zinc oxide (ZnO) is one of the most important materials due to its wide direct band gap (3.37 eV) and large exciton binding energy (60 meV) [6,7]. ZnO nanostructures have attracted more attentions for their applications in various nanodevices including nanogenerators, light-emitting diodes, polarization sensitive photodetectors, nanolasers, chemical sensors and solar cells [8][9][10][11][12][13][14][15][16][17][18]. Various synthesis methods such as thermal evaporation, chemical vapor deposition, metal-organic chemical vapor deposition, molecular beam epitaxy, template-assisted methods, electrochemical deposition and hydrothermal/solvothermal methods have been successfully applied in syntheses of ZnO nanostructures [19][20][21][22][23][24][25][26][27][28][29][30][31][32].…”