Low-temperature orientation-selective growth and ultraviolet emission of single-crystal ZnO nanowires

Abstract

We fabricated single-crystal ZnO nanowires at a low temperature of 500 °C without using any metal catalysts via the simple thermal oxidation of metallic Zn precursors. Scanning electron microscopy and high-resolution transmission electron microscopy (HRTEM) studies showed that the ZnO nanowires with orientation-selectivity grew laterally along the sides of the hexagonal-shaped ZnO matrix transformed from the metallic Zn precursors. It was found that the nanowires grew along the 〈112̄0〉 direction and were single crystals by HRTEM study. Typically, the lengths of the ZnO nanowires ranged from 0.5 to 3 μm and their mean diameter was 20±5 nm. Photoluminescence and cathodoluminescence measurements at room temperature showed a strong ultraviolet emission peak with negligibly weak green emissions, confirming that the individual ZnO nanowire was of excellent optical quality. Based on these results, we conclude that the simple thermal oxidation of metal Zn precursors is a useful, feasible approach for fabricating high-quality one-dimensional ZnO nanostructures for integration into nanophotonic integrated circuits.

Organization of Organic Molecules with Inorganic Nanoparticles: Hybrid Nanodiodes

“…[24] The photoluminescence of ZnO arises from the vacant oxygen sites. [25] Emission energy is low in doped nanoparticles (p-type) as compared to that in the pristine (n-type) case. The red-shift in the spectrum could be due to partly filling of vacant site with small Li ions.…”

CATALYST–FREE GROWTH OF WELL–ALIGNED ZnO NANOWIRES ON GRAPHENE/Si SUBSTRATEBY THERMAL EVAPORATION

“…Thus, for many applications of ZnO NWs in various areas, it is necessary to remove the catalysts nanoparticles from the NWs synthesized via a vapour-liquid-solid (VLS) mechanism; that is, catalysts-free growth of NWs is favorable for subsequent applications. However, until now it seems to be very difficult to synthesize the well-aligned NW arrays by catalyst-free methods, most these methods are commonly used to synthesize disarrayed nanostructures [23]. In this work, we will demonstrate that vertically well-aligned ZnO NW arrays can be synthesized on the graphene/Si substrate by simple thermal evaporation method.…”

Different morphologies of three dimensional ZnO structures synthesized by thermal evaporation method without a catalyst

“…수많은 세라믹 중에서 ZnO는 다 기능성 재료로서 상온에서 3.37 eV의 넓은 direct energy band gap과 large exciton binding energy(약 60 meV)를 갖고 있다. ZnO는 합성형태에 따라 [5], nanowire [6,7], nanotube [8], nanobelt [9], nanodisk [10], hollow structure cup [20] 등으로 구분되며, template-dependent hydrothermal method [20][21][22]와 thermal evaporation process [11,18,19] [11,23,25]. 또한 기상내 자가결합하여 생성된 ZnO HS는 기판과 무관하 게 생성됨은 leung에 의해 밝혀졌다 [26].…”