Three-Dimensional Cross-Linked Arrays of Comb-Like ZnO: Epitaxial Growth and Modulation

The method to construct the three-dimensional (3D) ordered nanostructure of ZnO for improving its performance has attracted considerable attention and remains a challenging issue, which has theoretical and practical implications for nanoscale applications such as optoelectronics and gas sensors. Herein, we demonstrate a straightforward chemical vapor deposition (CVD) technique for the epitaxial growth of 3D cross-linked comb-like ZnO arrays on r-plane sapphire substrates. The morphological, structural, and optical properties of the as-synthesized samples were examined using X-ray diffraction, field emission scanning electron microscopy, field emission transmission electron microscopy, Raman spectroscopy, UV-vis spectroscopy, and photoluminescence spectroscopy. A cooperative growth mechanism is suggested to construct 3D cross-linked comb-like ZnO arrays: The supersaturated alloy forms a backbone of oblique nanosails along [101<combining overline>0] by the Au-assisted catalytic vapor-liquid-solid (VLS) growth mechanism and the inevitable vapor-solid (VS) lateral extension growth process; simultaneously discrete nanoteeth are grown along the unilateral c-direction [0001] by the Zn self-catalytic VLS mechanism, culminating in a 3D cross-linked array of comb-like ZnO. The development of such a unique 3D cross-linked array allows the exploration of performance in gas-sensitive devices, optoelectronics, and quantum electrical information applications.