Facile synthesis of ZnO nano-structures: Morphology influence on electronic properties

ZnO samples with different nano-morphologies were synthesized by a facile method in which solutions containing zinc nitrate, ammonium hydroxide or hexamethylenetetramine were heated at different temperatures. Along with morphological and structural analysis, electrical and spectroscopic characterizations have been performed to investigate the role played by the sample morphologies. The spectroscopic results obtained during interaction with acetone well correlate with the electrical measurements: the higher is the intensity of the electronic absorptions in IR spectra, the higher is the electrical response to the tested gas. In particular, samples constituted by particles with well defined and smoothed surfaces are characterized only by the increase of electron population in the conduction band caused by acetone interaction and show peculiar energy barrier features. Samples constituted by particles with indented surfaces give the increase of electron population both in the conduction band and in oxygen vacancies. These last samples show similar energy barrier features.