Cathodoluminescence studies of band-A emission in thick undoped diamond epilayers grown on a large miscut substrate

Abstract

Variations have been observed in the optical properties of a 250 μm-thick diamond film grown by step-flow on a 10-degree miscut substrate. Cross section cathodoluminescence (CL) imaging reveals strong band-A emission throughout the first 6 μm of epitaxial growth, followed by inclined bands and clusters across the film thickness. Their recombination lifetimes are similar, suggesting that they originate from the same extended defect. Depth profile CL has been used to characterize the crystallographic orientation of the inclined bands and clusters. Mapping of the Raman shift of the C–C vibrational mode exhibits residual compressive strain of features in the same direction as the band-A emission tilted planes.