Synthèse par Sol-gel et caractérisation structurale et optique de nano poudres de ZnO pures et dopées en Aluminium (0.1, 0.5 , 0.75 , 1 , 5 , 7,10,15 et 20 % at).

Abstract

Nanomaterials present new physical properties which open up promising prospects in terms of application, whether in the field of magnetism, mechanics, catalysis or optics. This aroused our interest with, however, a certain demarcation from previous studies, almost all carried out on thin films of ZnO. The novelty is that our study focused on zinc oxide in the form of nanopowders, with the objective of developing and then investigating the structural and optical properties as well as the morphology of these nanopowders. For this we have developed nanopowders by chemical sol-gel method, these nanopowders and doped with different proportions of aluminum oxide and aluminum chlorine by diffusion method at calcination temperatures of 450, 500, 700,750 and 900 degrees CelsiusThe investigation was carried out by: X-ray, SEM, UV-visible, and infrared diffraction The results showed that the powders have a hexagonal structure (würtzite) and are of nanometric arrangementSolid solutions in which no new phase appears at 450 and 500 ° C, and this at low dopent, either starting from the doping of 7 percent or more, and at temperatures of 750 and 900 degrees Celsius, it shows a new phase of the spinelInoculation of ZnO nanopowders with aluminum oxide or chlorine showed a decrease in grainsize with an increase in concentration during spiking, and an increase in the effect of calcination temperature a also showed an increase in grain size and a sharp increase in doping. A scanning electron microscope study showed that nanopowders have a spherical shape. Its size decreases with the increase in the doping rate of aluminum. UV-visible characterizations show that the doped ZnO powders show an absorption edge around 380 nm. An optical gap decreases when aluminum is added. In conclusion, the nanopowders prepared reveal a good structural quality and a functional and optical aptitude for the application of these powders in the optoelectronic field.