Study of defects in GaN films by cross-sectional cathodoluminescence

Abstract

Cathodoluminescence (CL) in the scanning electron microscope has been used to study cross-sectional samples on GaN epitaxial films grown on sapphire. Increased CL emission, attributed to the presence of stacking faults and decorated dislocations, is observed in a region of the buffer layer close to the film-substrate interface, In the epilayers also a region of enhanced emission is observed which is partially caused by Si doping and in which structural defects are involved. Cross-sectional CL appears as a useful method to reveal features of the spatial distribution of luminescence, not detectable by plan-view measurements.