Effects of carbon on optical properties of ZnO powder

We report on C-doped ZnO, with different weight percentages of dopant, prepared by a high-energy ball milling method. The annealing conditions with temperature of 800 degrees C and in argon environment appear to be the optimal conditions for producing good quality crystals as well as pure UV emission. XRD and FTIR analysis indicate the substitution of C for Zn. In addition, Raman spectroscopy suggests a disordered graphitic layer covering the crystals. Photoluminescence investigation reveals the continuous quenching of visible region upon increasing C concentration and the intensity ratio between defect-related and UV emission can be as negligible as 0.02. The passivation of surface defects and the creation of a non radiative recombination pathway by carbon integration are proposed as possible origins of the suppression. (C) 2016 Elsevier B.V. All rights reserved.