Direct observation of large-scale nonuniformities in hydride vapor-phase epitaxy-grown gallium nitride by cathodoluminescence

摘要: Hydride vapor phase epitaxial GaN films grown on sapphire without a buffer are found to contain large-scale regions with high electron concentration located close the interface. These composed of individual columns forming an irregular but quasicontinuous layer, while rest film has much lower carrier concentration. The highly doped easily visualized using cathodoluminescence. coexistence low and allows us explain concurrent evidence quality in photoluminescence, Raman spectroscopy x-ray diffraction, measured transport studies.