Diameter‐ and density‐controlled synthesis of well‐aligned ZnO nanowire arrays and their properties using a thermal evaporation technique

Abstract

Vertically well-aligned ZnO nanowire (NW) arrays were synthesized directly on Si(100) substrate without any metal catalysts by conventional thermal evaporation. The effects of the substrate positions on the structures and properties of ZnO NW arrays were primarily discussed. The orientation and morphology of the resultant NWs were analyzed by using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results showed that the density and diameter of the ZnO NWs can be effectively controlled by changing the substrate position. The photoluminescence (PL) characteristics of the grown ZnO NW arrays show a sharp and strong ultraviolet (UV) emission at 380 nm and a very weak green emission at around 490 nm, indicating that the assynthesized NWs have outstanding optical properties with good crystalline quality and may have excellent application potential in optoelectronic devices.

Controllable and Rapid Synthesis of Long ZnO Nanowire Arrays for Dye-Sensitized Solar Cells

“…To realize these applications, the synthesis of ZnO nanowire arrays with desired morphology and properties is highly expected. So a great number of methods have been developed for synthesizing ZnO nanowire arrays, , including molecular beam epitaxy (MBE), chemical vapor deposition (CVD), , pulsed laser deposition (PLD), hydrothermal, and thermal evaporation , methods, among others. Among these methods, the hydrothermal method draws a particular interest for the advantages of low experimental temperature, high efficiency, easy adoption, and low cost, − with a potential for large scale.…”

Alignment nature of ZnO nanowires grown on polished and nanoscale etched lithium niobate surface through self-seeding thermal evaporation method

“…The well-aligned growth of ZnO nanowires in these regions can be attributed to the fact that a thicker ZnO seed layer has deposited along these regions of higher surface roughness as compared to defect-free areas on the surface of the substrate. A thicker ZnO seed layer directly contributes to better alignment of ZnO nanowires as mentioned in [33]. Hence, well-aligned growth of ZnO nanowires on lithium niobate is possible by controlled etching of the lithium niobate surface.…”

Shadow mask assisted direct growth of ZnO nanowires as a sensing medium for surface acoustic wave devices using a thermal evaporation method

“…It can be noted from figure 5(b) that most of the 1D ZnO structures formed in the investigated region had a diameter in the range of 1 μm which could be attributed to heavy vapor trapping by the sleeve and shadow mask during the growth process that led to an increase in the Zn vapor pressure in the region of the substrate. It is well-known that a higher Zn vapor pressure leads to an increase in the diameter of the ZnO nanowires nucleated [46].…”

“…However, a sparse growth of ZnO nanowires was observed on the LiNbO 3 surface which can again be attributed to the high Zn vapor pressure near the growth site caused by the near-adjacent presence of the shadow mask and sleeve. This is because the density of ZnO nanowires nucleated using the self-seeding thermal evaporation method generally reduces with an increase in Zn vapor pressure [46]. In the next growth trial, the distance p was further increased to the maximum possible value of 5 mm as depicted in the quartz boat arrangement shown in figure 8(a) and the device was loaded for nanowire growth.…”