Electronic and magnetic structure investigation of vanadium doped ZnO nanostructure

Abstract

In the present work, vanadium doped ZnO nanostructure, Zn1-xVxO (x = 0.00, 0.01, 0.02, 0.03) have been synthesized using sol-gel route. Rietveld refined X-ray diffraction confirms the single wurtzite phase for all the prepared samples with crystallite size ranging from 20 to 40 nm. UV-Diffuse reflectance spectroscopy shows the decrease in band gap energy from 3.20 to 3.17 eV on V doping and and Photoluminescence (PL) measurements has a strong visible emission region in the range 500-700 nm. PL broad peak in the visible region is further deconvoluted to study the defect states in the V:ZnO system. V doped ZnO nanostructure shows the room temperature ferromagnetism measured through Vibrating Sample Magnetometer hysteresis curve. The magnetic moment (mu(B)) is found to vary from 0.012 to 0.018 mu(B) per V-atom as x changes from 0.01 to 0.03 in Zn1-xVxO matrix. Magnetic structure properties are correlated with electronic transitions at different atomic levels using near-edge X-ray absorption fine-structure (NEXAFS) spectroscopy. NEXAFS spectral features at OK-, V/Zn L-3,L-2-edge reveals the hybridization of V(3d)-O(2p) orbitals and absence of V-metallic clusters in V:ZnO system. These investigations further envisage the existence of +5 state of vanadium in Zn1-xVxO nanostructure.