Intense photoluminescence of slightly doped ZnO–SiO2 matrix

ZnO nanocrystals are embedded in an amorphous matrix of SiO2 using the sol-gel method and their optical properties were studied. A strong Blue-violet luminescence was observed. The photoluminescence’s maximum, located at 400 nm approximately, depends on the rate of the gelation process and also shows a slight dependence with the wavelength of excitation. The mean size of ZnO particles is about 27 nm leading with a weak quantum confinement. XRD patterns did not reveal the presence of ZnO particles but TEM investigation demonstrates agglomeration of ZnO crystallites in the composite with different sizes and shapes.