title: EPR, thermo and photoluminescence properties of ZnO nanopowders.
abstract: Nanocrystalline ZnO powders have been synthesized by a low temperature solution combustion method. The photoluminescence (PL) spectrum of as-formed and heat treated ZnO shows strong violet (402, 421, 437, 485 nm) and weak green (520 nm) emission peaks respectively. The PL intensities of defect related emission bands decrease with calcinations temperature indicating the decrease of Zn(i) and V(o)(+) caused by the chemisorptions of oxygen. The results are correlated with the electron paramagnetic resonance (EPR) studies. Thermoluminescence (TL) glow curves of gamma irradiated ZnO nanoparticles exhibit a single broad glow peak at ∼343°C. This can be attributed to the recombination of charge carriers released from the surface states associated with oxygen defects, mainly interstitial oxygen ion centers. The trapping parameters of ZnO irradiated with various γ-doses are calculated using peak shape method. It is observed that the glow peak intensity increases with increase of gamma dose without changing glow curve shape. These two characteristic properties such as TL intensity increases with gamma dose and simple glow curve structure is an indication that the synthesized ZnO nanoparticles might be used as good TL dosimeter for high temperature application.
authors.affiliation: Department of Physics, M.S. Ramaiah Institute of Technology, Bangalore 560 054, India.
authors.forename: A
authors.initials: A
authors.lastname: Jagannatha Reddy
authors.forename: M K
authors.initials: MK
authors.lastname: Kokila
authors.forename: H
authors.initials: H
authors.lastname: Nagabhushana
authors.forename: J L
authors.initials: JL
authors.lastname: Rao
authors.forename: C
authors.initials: C
authors.lastname: Shivakumara
authors.forename: B M
authors.initials: BM
authors.lastname: Nagabhushana
authors.forename: R P S
authors.initials: RP
authors.lastname: Chakradhar
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D008163:Luminescent Measurements; D008954:Models, Biological; D053758:Nanoparticles / Q000737:chemistry*; D055668:Photochemical Processes; D011208:Powders; D013819:Thermoluminescent Dosimetry; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D011208:Powders; D015034:Zinc Oxide