Photo-induced EPR study of electron trap in ZnO nanoparticles

Defect and impurity associate wide band gap semiconductor ZnO are potential impact in the field of quantum information science, optoelectronic, atomic transport and cancer treatment process. In ZnO, zinc vacancies (VZn) are tetrahedrally surrounded by four O2− in the basal plane. Suppose the substituted hydrogen (HO) or interstitial hydrogen (Hi) bound with VZn leads to provide different paramagnetic nature. At room temperature, two electron paramagnetic resonances (EPR) donor signals overlapping at g 1.9573 and of 77 K the peaks are distinguish at 1.9562 and 1.96. At 77 K, (i) both the peak intensities are increases indicates that the increases of paramagnetic behavior by reducing temperature (ii) the peak intensity observed at 1.9562 is strongly increased upon uν illumination with increases of uncompensated electron spin from acceptor to donor level. Similarly, acceptor related paramagnetic signals observed at 2.0138 and 2.0044 under uν illumination at 77 K, because the concentration of the donor is hig...