Catalyst-assisted heteroepitaxial strategy for highly ordered β-Ga2O3 nanoarrays and their optical property investigation

Abstract

In this work, we demonstrate the growth of highly ordered β-Ga2O3 nanoarrays with (001) preferred growth plane for the first time through a facile heteroepitaxial strategy using metal Ga and c-sapphire as Ga precursor and monocrystalline substrate. The (001) preferred growth plane means that the β-Ga2O3 nanowires grow along the normal direction of the (001) plane. The β-Ga2O3 nanoarrays along (001) preferential plane exhibit inclined six equivalent directions that correspond to the six crystallographic symmetry of (0001) α-Al2O3. High-resolution transmission electron microscopy analyses confirm the good crystallinity and the existence of unusual epitaxial relationship of {310} β-Ga2O3 ǁ (0001) α-Al2O3 and <001> β-Ga2O3 or <132> β-Ga2O3 ǁ [100] α-Al2O3. UV–vis and cathodoluminescence measurements reveal the wide band gap of 4.8 eV and the strong UV-blue luminescence (300–500 nm) centered at ∼388 nm. Finally, the luminescence mechanism is further investigated with the assistance of x-ray photoelectron spectroscopy. The heteroepitaxial strategy of highly ordered β-Ga2O3 nanoarrays in this work will undoubtedly pave a solid way toward the fundamental research and the applications of Ga2O3 nanodevices in optoelectronic, gas sensor, photocatalyst and next-generation power electronics.