Abstract

A-plane-oriented ZnO epilayers grown by plasma-assisted molecular beam epitaxy were studied with respect to their optical properties. 10K-photoluminescence (PL) and reflectivity were used to analyze various 2 µm-thick ZnO films etched at different etching profile. The PL spectra show the band emission of the structures become narrower when the etching profile increase. At 0.75 µm etching profile, two structures at 3.38 eV corresponding to the A-free exciton transition and at 3.41 eV corresponding to the B-free exciton transition and the Y line were observed in the 10K PL spectrum providing that the optical properties of the ZnO sample are preserved and enhanced.

Key words: Excitonic, photolumescence, wet-chemical etching, a-plane ZnO.