Quasi-Van der Waals Epitaxial Growth of GaN on Hexagonal Boron Nitride via Metal-Organic Chemical Vapor Deposition

Herein, GaN grown on hexagonal boron nitride (h-BN) layer is investigated through surface treatment to improve the quality of the GaN layer. The surface treatment method comprises the annealing and nitridation methods. The surface bonding property of the h-BN layer is confirmed after surface treatment methods by X-ray photoelectron spectroscopy. These conditions affect the formation of the N-H bond and limit the N-O bonding. For the X-ray diffraction results of the GaN template on the h-BN layer, the full width at half maximum of the GaN (002) plane significantly decreases with the surface treatment of the h-BN layer, whereas that of the GaN (102) plane changes slightly. Moreover, the Raman spectra are measured to confirm the stress relaxation caused by the effect of quasi-van der Waals (QvdW) epitaxy between the GaN and h-BN layers. The GaN/h-BN with surface treatment has smaller compressive strain value than GaN/sapphire. The QvdW epitaxy between the GaN and h-BN layers affects the improvement of the GaN quality on h-BN layer owing to the increased dangling bond density with surface treatment. Therefore, this indicates that the GaN grown on the h-BN layer is QvdW epitaxy.