Controlled Growth of Zinc Oxide Nanostructures for Applications*

Zinc Oxide (ZnO) has proven to be a versatile functional material with promising properties. Here we discuss about the controlled growth and applications of various ZnO nanostructures including novel ZnO nanotubes (NTs) and nanosquids (NSqs). We use a conventional thermal CVD technique for the synthesis of ZnO nanostructures. We found that ZnO nanowires, nanobelts and nanocombs can be readily obtained by applying appropriate gas flow rates and growth temperatures.\footnote{S. L. Mensah et al, J. Phys. Chem. C (Letter) 111, 16092 (2007).} ZnO NTs and NSqs can be formed on the substrates when appropriate cooling rate was applied.\footnote{S. L. Mensah et al, Appl. Phys. Letts. 90, 113108 (2007).} These nanostructures were characterized using XRD, HRTEM, FESEM, Raman spectroscopy, and photoluminescence. Results show that ZnO nanostructures were single crystals in wurtzite structure. Among these ZnO NWs were found to be excellent electron field emitters and field effect transistors.