Defect induced band gap narrowing of zinc oxide nanoparticle using mg 2+, ca 2+ and sr 2+ metal ions as dopant

Abstract

The main objective of this study was to investigate the lowering of the band gap energy and optical properties of ZnO doped with alkaline earth metals (Ca 2+ , Sr 2+ , Mg 2+ ). ZnO nanoparticle was synthesize by adding Zinc acetate to aqueous NaOH solution and subjected to ultrasonic irradiation for 2 hr after that a white precipitate was obtained which was filtered and washed with ethanol and de-ionized water and dried in an oven at 60 0 C for 3 hr. The dried white powder was then calcined at 400 o C for 2 hr and subjected to UV-Vis spectrophotometer used to characterize the synthesized ZnO nanoparticle and the band gap energy of ZnO undoped and doped with alkaline earth metals (Ca 2+ ,Sr 2+ ,Mg 2+ ) was determined. From all dopants 0.006 M Mg 2+ doped ZnO nanoparticles was found to be narrowing band gap more.