Large-Scale Synthesis of Bicrystalline ZnO Nanowire Arrays by Thermal Oxidation of Zinc Film: Growth Mechanism and High-Performance Field Emission

Abstract

Understanding the origin crystal nucleation and driving force is critical for the synthesis of one-dimensional nanomaterials with controllable size, morphology, and crystal structure. The growth behavior of ZnO nanowires prepared by thermal oxidation of zinc film is studied. It is found that the grown nanowires have a bicrystalline structure and growth direction significantly different from the commonly observed [0001] direction. On the basis of detailed high resolution morphology and structural analysis, we propose the origin of the initial growth site, as well as the driving force for formation of the bicrystalline structure of aligned ZnO nanowires. The initial zinc film plays an important role in the growth of nanowire. The edge-enhanced oxidation effect of zinc grain initiates the ZnO nanowire nucleation. The strain within the ZnO layer drives and stimulates the nanowire growth. The present study provides insight into the growth mechanism of ZnO nanowires grown from thermal oxidation of zinc film. Field emission measurement results show that the prepared ZnO nanowires have excellent field emission properties. Uniform emission can be obtained and the turn-on field is 7.8 V/μm. The results indicate that the method is advantageous for large-scale synthesis of ZnO nanowires for field emission applications.

The Analysis and Research for the Plate Differential Oxygen Gas Sensor of Auto Based on the Temperature Field and Thermal Stress Field

“…Some sensors live up to 100 thousand kilometers. According to the average life span of 80 thousand kilometers, if a car runs 40 thousand kilometers per year, for about 2 years, it will need to replace the new oxygen sensors [29].According to environmental protection requirements, oxygen sensors must be installed in the newly manufactured gasoline vehicles [23].Some of the models in the three way catalytic converter (TWC) before and after each equipped with an oxygen sensor, which uses hydrogen peroxide sensor [30].According to the current domestic car ownership base and the number of new cars every year, it is estimated that 100 million oxygen sensors are needed per year [24].Although there are hundreds of manufacturers of oxygen sensors in China, the quality of the sensors produced is not up to the advanced level in other countries [25].At present, Germany BOSCH, the United States DELPHI, Japan DEOSO and Japan NGK occupy the sensor market [22].…”

ZnO Micro- and Nanostructures Obtained by Thermal Oxidation: Microstructure, Morphogenesis, Optical, and Photoluminescence Properties

“…For instance, on controlling reaction temperature, cooling rate, or processing atmosphere chemistry, wires [5], needles [6], sphere-shape grains [7], hexagonal and cylindrical prisms [8], multipods [9], whiskers [10], and urchinlike particles [11] have been fabricated. In this regard, ZnO structures obtained through thermal oxidation have been applied in lasing [12,13], light guide [14], photodetection [15], field emission [16], Schottky barriers [17], gas sensing, and photocatalysis [18]. Nevertheless, the extensive variation of experimental parameters used to obtain ZnO micro-and nanostructures by this technique hampers the generation of a compendium of the growth mechanisms involved when specific processing parameters are used, which ultimately determines the resulting morphology.…”

Enhanced Field Emission from UV-Illuminated CuO Nanowires Fabricated by Thermal Oxidation of Cu Film

“…[1][2][3][4] Since the¯rst discovery of facile preparation of cupric oxide (CuO) nanowires on Cu substrate by direct thermal oxidation method in air, many metallic oxide nanowires have been reported by this technique. [5][6][7][8] Naturally oxidizing environments have many advantages in synthesizing metallic oxide materials, such as technical simplicity, large scale growth capability, and compatibility with microfabrication process. Among the variety of metallic oxide nanowires, CuO nanowires with monoclinic structure are a type of p-type semiconductor with a narrow band gap of 1.2 eV, and they are widely used in many applications, such as¯eld emission, gas sensor, catalysis, and lithium ion battery.…”