Catalyst-assisted heteroepitaxial strategy for highly orderedß-Ga2O3nanoarrays and their optical property investigation.

In this work, we demonstrate the growth of highly orderedß-Ga2O3nanoarrays 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 theß-Ga2O3nanowires grow along the normal direction of the (001) plane. Theß-Ga2O3nanoarrays 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}ß-Ga2O3ǁ (0001)α-Al2O3and <001>ß-Ga2O3or <132>ß-Ga2O3ǁ [11¯00]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 orderedß-Ga2O3nanoarrays in this work will undoubtedly pave a solid way toward the fundamental research and the applications of Ga2O3nanodevices in optoelectronic, gas sensor, photocatalyst and next-generation power electronics.