Optical and structural properties of lateral epitaxial overgrown GaN layers

Abstract

The optical and microstructural properties of laterally grown GaN overlayers nucleated on GaN stripes by organometallic vapor-phase epitaxy have been investigated. TEM studies indicate that the high density of threading dislocations in the GaN substrate originating at the underlying interface of GaN with the AlN buffer layer, propagate through the window overgrown region. In contrast, the dislocation density is substantially lower in the laterally grown region. Spatially resolved Raman scattering results are consistent with improved material quality on the laterally overgrown region. Low-temperature photoluminescence measurements show that a shallow acceptor is present in the selectively grown region.