NEAR-BAND-EDGE EMISSION OF MECHANICALLY MILLED AND THERMALLY ANNEALED ZnO:Ge PARTICLES

Abstract

This paper reports a novel way for the synthesis of Ge doped ZnO particles by a mechanically milled Ge and ZnO powder mixture (ZnO:Ge) followed by thermal annealing in Ar + 5%H₂ to achieve near-band-edge (NBE) emission of ZnO with controllable intensities. The Ge doped ZnO particles were synthesized by mechanical milling of a ZnO and Ge powder mixture up to 50 h in particularly, using different ZnO:Ge ratios and annealing temperatures. The Ge doped ZnO particles were observed to have a rounded morphology with a diameter of ~500 nm when an annealing temperature of 1000^oC was used. The Ge doped ZnO particles showed NBE emission of ~380 nm with a suppressed visible band of ~500 nm as a function of the Ge content and annealing temperatures. These results suggest that the current method is very useful for synthesis of Ge doped ZnO particles to obtain NBE emission, which is of particular importance for potential application in the optoelectronic and UV detector field.