MicroRaman and phase stepping microscopy analysis of growth defects in GaAs/GaAs epilayers

Abstract

Oval defects in GaAs layers grown by molecular beam epitaxy (MBE) are characterised using a morphological technique, phase stepping microscopy (PSM) and a structural technique, microRaman spectroscopy. The oval defects were classified depending on the existence of a core. This results in different defect morphologies, showing a strongly irregular growth interface for the core regions and different crystal structures, revealing a polycrystalline structure at the core. Faceted parts of the defects are indexed and structurally probed, showing that they present a good crystalline quality.