Evolution of ZnO nanoparticles and nanorods: aspect ratio dependent optoelectronic properties
Nanoscience Laboratory, Department of Physics, Tezpur University, P.O. Napaam, Tezpur 784028, Assam, India
Corresponding author: email@example.com
Accepted: 6 October 2010
Published online: 23 December 2010
Zinc oxide (ZnO) nanorods, with different aspect ratios, were synthesised at room temperature via an inexpensive physico-chemical route. The source material was a mixture of zinc acetate dihydrate [ Zn (CH3 COO)2 2H2O] , cetyl-trimethyl ammonium bromide [ C19H42BrN] , and sodium hydroxide [NaOH]. The length of the nanorods, as a result of restricted directional growth, was controlled by means of varying the molar ratios of the reactants. As revealed by X-ray diffraction measurements, the as-grown ZnO nanorods exhibited wurtzite crystalline phase, with preferred crystallographic orientation along (101) plane. The visual evidence of the formation of ZnO nanorods was confirmed by transmission electron microscopy studies. The photoluminescence spectra of the ZnO systems show two prominent peaks: a sharp peak located at ~375 nm (UV band) and a broad band peaking at ~480 nm (green band). The UV-to-green PL intensity ratio was found to be improved with enhanced aspect ratio. The aspect ratio dependent tunable optical responses would provide better insight to understand the radiative and non-radiative processes in elongated nanosystems.
© EDP Sciences, 2010