An attempt was made to detect the defects in ZnO nanoparticles, synthesized by the conventional co-precipitation route, using various spectroscopic techniques. The broad emission peak observed in photoluminescence spectrum and the non zero slope in Williamson-Hall analysis indicate the defects induced strain in the ZnO lattice. A few additional modes observed in Raman spectrum could be due to the breakdown of the translation symmetry of the lattice caused by defects and/or impurities. The presence of impurities could be ruled out as X-ray diffraction patterns revealed a pure wurtzite structure. The presence of the vibrational band related to the Zn vacancies (VZn), unintentional hydrogen dopants and their complex defects confirmed the defects in ZnO lattice. Positron life time components τ1 and τ2 additionally support VZn attached to hydrogen and to a cluster of Zn and O di-vacancies respectively.

Studies on Intrinsic Defects Related to Zn Vacancy in ZnO Nanoparticles. Singh, V.P., Das, D., Rath, C.: Materials Research Bulletin, 2013, 48[2], 682-6