Synthesis and characterization of semiconductor oxide 1-D nanostructures by vapor transport method

Abstract

Nanostructures have received steadily growing interest as a result of their peculiar and fascinating properties superior to their bulk counterparts. There are a large number of opportunities that might be realized by making new types of nanostructures. It is generally accepted that quantum confinement of electrons by the potential wells of nanometer-sized structures may provide one of the most powerful (and yet versatile) means to control the electrical and optical properties of a solid-state functional material. Efficient exploitation of this scientific fact in emerging potential applications of semiconducting oxide nanostructures requires careful size and morphology control and exploring unique chemical and physical properties of pure and doped nanostructures. In this research, semiconductor oxide 1-D nanostructures have been investigated, prime focus being their synthesis. These nanostructures have been characterized in terms of photoluminescence and gas sensing properties. Zinc oxide nanostructures were synthesized by vapor transport method using ZnO and carbon mixture as source material. A systematic increase in diameters is observed for all the nanostructures when Ar flow is gradually increased. Possible reason proposed for the increase in diameter is increase in Zn vapor flux with higher flow rates. Morphological control is possible by placing the substrates in different temperature zones. Single crystalline Nanocombs, Nanowires and nanorods were formed in the high, intermediate and low temperature zones respectively. Morphology and structure of ZnO nanostructures were investigated using scanning and transmission electron microscopes. Room temperature photoluminescence has also been demonstrated for these nanostructures. Post annealing of pure ZnO nanostructures is important as it provides an insight and help in explaining the growth kinetics and enhancement of different properties. Systematic SEM studies of unique nanocomb-shape dendrites after periodic...