Enhanced adhesion and field emission of CuO nanowires synthesized by simply modified thermal oxidation technique

Abstract

Metal oxide nanowires (NWs) can be easily grown by the thermal oxidation method, but the low adhesion between the NWs and the substrate restricts their practical applications in functional devices. In this work, the conventional hotplate technique is simply modified by introducing one or two stainless steel plates to supply a more stable oxidation environment, which is found to be beneficial to the growth and adhesion of CuO NWs on the Cu substrate. In detail, the Cu foils were heated on the hotplate directly, on one plate over the hotplate, and between two plates over the hotplate at 400 °C in ambient condition. It is found that the NWs obtained between two plates exhibit large length and diameter with moderate density. The sufficient activated oxygen, stable temperature, and proper temperature gradient configuration caused by the two plates accelerate the formation of CuO NWs, and result in the longest NWs with enhanced adhesion. The grain-boundary diffusion and Kirkendall effect are proposed to explain the mechanism of NWs growth and the formation of cracks. The NWs obtained between two plates also showed the best field emission properties, with lowest turn-on field (5.31 V μm(-1)) and threshold field (9.8 V μm(-1)). Excellent field emission properties and enhanced NW-substrate adhesion indicate that these NW arrays could be potentially used as the cathode of field emission displays.

The Phase Evolution and Physical Properties of Binary Copper Oxide Thin Films Prepared by Reactive Magnetron Sputtering

“…However, as $\phi$ > qV , a direct current will arise. In order to analyze the properties of the field emission, the following F–N equation is generally used [31,32,33,34]:$J=\frac{A{\beta }^2{E}^2}{{\varphi }_s}\exp (\frac{-B{\phi }_{}{}^{3/2}}{\beta E})$…”

Electron Emission Devices for Energy‐Efficient Systems

“…In the last couple of decades, large number of new materials and composites have been studied to reveal their field emission performance including different metals, semiconductors, metal oxides, sulfides, carbides, nitrides, ferrites, perovskite solids, hexaborides, and so on. Apart from these materials, low‐dimensional materials are getting significant attention recently.…”

“…Studies have shown that annealing atmosphere engineering remarkably improved field emission in TiO 2 , ZnO, and graphene . In addition, annealing atmosphere engineering can promote adhesion for durable contact between base substrate and the emitters, especially nanotubes; thus, it can increase overall device stability and endurance …”

Fabrication of periodic arrays of needle-like Si nanowires on (001)Si and their enhanced field emission characteristics

“…The results clearly demonstrated that the eld emission property of vertical Si nanowires was greatly enhanced aer the multiple ACER cycle process, mainly due to the formation of sharp-tip structures. Compared with previously reported data, the turn-on eld value of the periodic arrays of vertical tapered Si nanowires aer the 4 th ACER cycle (1.3 V mm À1 ) obtained in this study is much lower than that of most Si-based nanostructures (2.1-16.5 V mm À1 ), [3][4][5][6][7][8][9][10][30][31][32][33][34][35] and other semiconductor nanostructures, such as CuO nanowires (5.3-8.6 V mm À1 ), 36,37 ZnO nanopencils (3.2-3.7 V mm À1 ), 38,39 and GaN nanoneedles (3.5-9.0 V mm À1 ). 40,41 However, it should be noted from Fig.…”