Characterization of ZnO nanowires obtained by a two stage method

G. A. CUELLAR MURILLO; M. F. BIANCHETTI; E. A. HEREDIA; C. D. BOJORGE; N. E. WALSÖE DE RECA

Buenos Aires

Congreso; 15th International Meeting on Chemical Sensors; 2014

CNEA

The growth of zinc oxide (ZnO) nanowires / nanorods by hydrothermal method has two advantages: low temperature growth and synthesis on large areas. In this paper, nanowires / nanorods were obtained from ZnO thin films prepared by sol- gel method on different silicon substrates. From these films, which serve as seed layers, nanowires / nanorods of ZnO grow by hydrothermal method. Pure and oxidized silicon (111) were used as substrates. In these last substrates a SiO2 thin layer of 0.3 microns was formed by wet oxidation to electrically isolate the film from the substrate. Two precursor solutions were prepared: ? zinc acetate dihydrate in ethanol , adding additives such as acetic acid, lactic acid and diethanolamine . (X solution) [1] ? zinc acetate dihydrate in monoethanolamine and isopropanol (M solution) [2] Each solution, after an aging for 24 h, was deposited on the substrates using the spin coating method and making films of 1 and 5 layers. To consolidate the films a preheat treatament at 200 °C was made between layers. Thereafter, samples were subjected to a final heat treatment at 450 °C to achieve ZnO crystallization and the elimination of organic residues. Substrates with seed layers were immersed in a solution of zinc nitrate hexahydrate with hexamethylenetetramine (HMT) [3 ] and heated in a bath at 75 °C and then obtaining oriented nanowires / nanorods.