Abstract
The effective and scalable assembly of 1D nano-units into ordered 3D monocrystalline networks remains a challenge. Based on the crystal structure and growth characteristics of GaN, we have designed a specific epitaxy strategy and successfully achieved large area self-networking of 3D monocrystalline nanostructure on Au-coated β-LiGaO2 (100) substrate formed by the interconnection of GaN nanobelts grown along three equivalent directions of the m-axis [011̅0], [101̅0] and [11̅00]. This well-aligned 3D GaN nanostructure grown by simple CVD method has good reproducibility and the yield of cross-linked junctions are quite high. The mono-crystallinity of this structure were proved by X-ray diffraction (XRD) and transmission electron microscope (TEM) results, especially at the crosslinked junctions. The overall epitaxial relationships between GaN and LiGaO2 was analyzed and the defect-mediated anisotropic VS growth mechanism was deduced from thorough characterization of individual nanobelts. Besides, the morphology of 3D GaN nanostructure including length, width and height was found to be controllable. The E2 (high) phonon peak at 567.4 cm−1 in the Raman spectrum and the strong ultraviolet emission peak centered at 363.3 nm (3.41 eV) in the photoluminescence (PL) spectrum indicate that the 3D GaN nanostructures are nearly strain-less and have high crystalline quality. This large-scale 3D monocrystalline network not only retains the advantage of 1D nanomaterials, but also become easier to operate compared with individual nanowire. The epitaxy assembly strategy is expected to ensure the property homogeneity of chip-scale devices for their real applications and provide a reference for further growth of tunable 3D structures of other materials.
Published Version
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