Fabrication of green and orange photoluminescent, undoped ZnO films using spray pyrolysis

Abstract

Photoluminescent, undoped ZnO films have been fabricated using spray pyrolysis of zinc nitrate solution. The luminescent films had a polycrystalline hexagonal wurtzite type structure with no preferred orientation. Photoluminescence intensity was critically dependent on substrate temperature during spray pyrolysis and on post-annealing temperature. Green, photoluminescent films possessed a porous structure while orange films possessed a close packed granular morphology. Green luminescence appears to be due to oxygen vacancies in a layer just below the crystallite surface.