title: Luminescence studies and EPR investigation of solution combustion derived Eu doped ZnO.
abstract: ZnO:Eu (0.1 mol%) nanopowders have been synthesized by auto ignition based low temperature solution combustion method. Powder X-ray diffraction (PXRD) patterns confirm the nanosized particles which exhibit hexagonal wurtzite structure. The crystallite size estimated from Scherrer's formula was found to be in the range 35-39 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies reveal particles are agglomerated with quasi-hexagonal morphology. A blue shift of absorption edge with increase in band gap is observed for Eu doped ZnO samples. Upon 254 nm excitation, ZnO:Eu nanopowders show peaks in regions blue (420-484 nm), green (528 nm) and red (600 nm) which corresponds to both Eu2+ and Eu3+ ions. The electron paramagnetic resonance (EPR) spectrum exhibits a broad resonance signal at g=4.195 which is attributed to Eu2+ ions. Further, EPR and thermoluminescence (TL) studies reveal presence of native defects in this phosphor. Using TL glow peaks the trap parameters have been evaluated and discussed.
authors.affiliation: Department of Physics, M.S. Ramaiah Institute of Technology, Bangalore 560 054, India. Electronic address: ajreddy09@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Jagannatha Reddy
authors.affiliation: Department of Physics, Bangalore University, Bangalore 560 056, India.
authors.forename: M K
authors.initials: MK
authors.lastname: Kokila
authors.affiliation: Centre for Advanced Materials Research, Tumkur University, Tumkur 572 103, India.
authors.forename: H
authors.initials: H
authors.lastname: Nagabhushana
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: C
authors.initials: C
authors.lastname: Shivakumara
authors.affiliation: National Aerospace Laboratories (CSIR), Bangalore 560 017, India.
authors.forename: R P S
authors.initials: RP
authors.lastname: Chakradhar
authors.affiliation: Department of Chemistry, M.S. Ramaiah Institute of Technology, Bangalore 560 054, India.
authors.forename: B M
authors.initials: BM
authors.lastname: Nagabhushana
authors.affiliation: Department of Chemistry, M.S. Ramaiah Institute of Technology, Bangalore 560 054, India. Electronic address: rhk.chem@gmail.com.
authors.forename: R
authors.initials: R
authors.lastname: Hari Krishna
mesh_terms: D003198:Computer Simulation; D004578:Electron Spin Resonance Spectroscopy; D005063:Europium / Q000737:chemistry*; D005720:Gamma Rays; D007700:Kinetics; D049449:Luminescence; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D011208:Powders; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D014961:X-Ray Diffraction; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D011208:Powders; D012996:Solutions; D005063:Europium; D015034:Zinc Oxide
keywords: EPR; Nanopowder; Photoluminescence; Thermoluminescence; ZnO