Excitonic properties of the polar faces of bulk ZnO after wet etching

Abstract

We examine the effects of acid etchants on the two polar faces of bulk ZnO using photoluminescence and reflectance spectroscopy, as well as changes in surface topography using atomic-force microscopy. Although the (000-1) surface exhibits intense bound-exciton emission and strong free-exciton resonances, these are quenched for the (0001) surface. We attribute this to the polish quality of each polar face, and compare the effects of each etchant solution on surface topography and excitonic features. © 2003 Elsevier B.V. All rights reserved.