Effect of Oxygen vacancy induced defect on the optical emission and excitonic lifetime of intrinsic ZnO

Abstract

Intrinsic Zinc Oxide (ZnO), being a direct large band gap material, having the enough amount of occupant defect states arising from non-stoichiometric zinc and oxygen, has came forward as an effectual heterogeneous photoluminescent material weigh against to other semiconductor oxides. This change of orientation of the XRD peak from <002> direction to <101> and <103> may constructs on account of the raise in the Zn-to-ZnO ion ratio within the ZnO matrix by the possible de-oxygenation of ZnO at particular calcination temperature. The larger Zn interstitial defects (Zni, Zni+) creates the violet (I & II) components for as synthesized ZnO while the O vacancy (VO) methodically boosts the green emission at superior calcination temperature. The decrease in carrier lifetime from 206 ps to 21 ps as obtained by the time resolved photoluminescence spectra takes place due to O-vacancy induced defect-related recombination. The high-concentration O-vacancy defect which manufactures the <103> crystallographic orientation and the consequential strong green PL emission are anticipated to advance clarification of the mechanisms of defect related emission and inflate the opto-electronic applications of ZnO.