A Novel Synthesis of ZnO Nanoflower Arrays Using a Lift-Off Technique with Different Thicknesses of Al Sacrificial Layers on a Patterned Sapphire Substrate

Abstract

A novel method to synthesize large-scale ZnO nanoflower arrays using a protrusion patterned ZnO seed layer was investigated. Different thicknesses of aluminum (Al) film were deposited on the concave patterned sapphire substrate as a sacrificial layer. ZnO gel was layered onto the Al film as a seed layer and OE-6370HF AB optical glue was used as the adhesive material. A lift-off technique was used to transfer the protrusion patterned ZnO/AB glue seed layer to a P-type Si <100> wafer. The hydrothermal method using Zn(CH3COO)2 and C6H12N4 solutions as liquid precursors was used to synthesize ZnO nanoflower arrays on the patterned seed layer. X-ray diffraction spectra, field-effect scanning electron microscopy, focused ion beam milling (for obtaining cross-sectional views), and photoluminescence (PL) spectrometry were used to analyze the effects that different synthesis times and different thicknesses of Al sacrificial layer had on the properties of ZnO nanoflower arrays. These effects included an increased diameter, and a decreased height, density (i.e., number of nanorods in μm−2), total surface area, total volume, and maximum emission intensity of PL spectrum. We showed that when the synthesis time and the thickness of the Al sacrificial layer were increased, the emission intensities of the ultraviolet light and visible light had different variations.

Antibacterial and Anti-Inflammatory Properties of ZnO Nanoparticles Synthesized by a Green Method Using Sargassum Extracts

“…These and other properties can be improved when ZnO is at the nanometric scale. In this sense, the synthesis of nanoparticles (NPs) [ 4 ], nanowires [ 5 ], nanostars [ 6 ], and nanoflowers [ 7 ] have been reported. ZnO nanoparticles have been widely studied due to their catalytic [ 8 ], antibacterial [ 9 ], and antiviral [ 10 ] properties, which largely depend on their size and morphology.…”

Synthesis of ZnO Nanoflower Arrays on Patterned Cavity Substrate and Their Application in Methylene Blue Degradation

“…The drawings of the UV–visible diffusion reflectance spectra of ZnO NFAs for samples with different synthesis times are shown in Figure 8 a and their corresponding Tauc plots are shown in Figure 8 b. UV–visible diffusion reflectance spectra of ZnO NFAs reveal the optical reflectance in the UV region which can be recognized as the migration of electrons from the valance band to the conduction band [ 12 ]. These UV–visible spectra reveal that their reflectance rates increase with the synthesis time of ZnO NFAs.…”

“…A significant finding of this research is the development of an inexpensive technique to create a ZnO seed layer with a matrix and protrusion structure for synthesizing ZnO NFAs using a combination of template technology and the hydrothermal method for synthesizing one-dimensional ZnO-based nanomaterials. This approach involves the uses of patterned sapphire as templates and lift-off as the technology to create ZnO NFAs [ 11 , 12 ]. The synthesis results of ZnO NFAs were analyzed by varying the synthesis time while keeping the other parameters constant [ 13 ].…”

Synthesis of ZnO Nanoflower Arrays on a Protrusion Sapphire Substrate and Application of Al-Decorated ZnO Nanoflower Matrix in Gas Sensors

“…To understand the underlying reasons for this observation, further investigations are needed. Previous studies have indicated that different mechanisms can lead to various emissions in ZnO-based materials [20,21]. We conducted X-ray photoelectron spectroscopy (XPS) to analyze the chemical bonding state of oxygen in order to investigate the effect of synthesis time.…”

“…To understand the underlying reasons for this observation, further investigations are needed. Previous studies have indicated that different mechanisms can lead to various emissions in ZnO-based materials [ 20 , 21 ].…”