Controlling the Crystallite Size of Zinc Oxide Nanorods via Chemical Bath Deposition and Post-Hydrothermal Treatment

Abstract

ZnO nanorods were deposited on ITO glass substrate via chemical bath deposition at low temperature of 90°C. The seeding solution was made by dissolving zinc nitrate tetrahydrate and methenamine in cool water (5°C). The as-synthesized ZnOs were further subjected to post-hydrothermal treatment series.The results of scanning electron microscope (SEM) studies showed that the ZnO nanorods were grown as vertically-aligned hexagonal structure, while x-ray diffraction (XRD) patterns showed a high intensity of [002] peak. The absorption spectra of the as-synthesized sample indicated a strong absorption peak near the UV region. After post-hydrothermal treatments, the absorption was slightly shifted to visible region. The ZnO nanorods sample derived from post-hydrothermal treatment at 150°C for 12 hours has the largest crystallite size of 269.402 nm and the lowest band gap energy, Egvalue of 3.205 eV.

Optimizing the Nanostructural Characteristics of Chemical Bath Deposition Derived ZnO Nanorods by Post-Hydrothermal Treatments

“…4, where the extrapolation of linear parts of the curves to the energy axis provides an estimated band gap energy of 3.63 eV for the as-deposited sample, and 3.15, 3.12 and 3.07 eV for the samples with post-hydrothermal treatments for 3, 6 and 9 hours, respectively (Table 2). The results presented in Table 1 and 2 confirm that the crystallite size of semiconductor nanostructures significantly affects their band gap energies, as has been observed with our previous studies with CBD derived ZnO nanorods [14], pre-hydrothermally treated ZnO nanoparticles [19],…”

“…By using CBD, Lang et al [9] have successfully grown ZnO nanorods on Si (100) substrate, where the growing solution was prepared at low temperature of 5 o C. However, the resulting nanorods still grew in a rather random orientation and lack of crystallinity. In our previous work [14], we have combined CBD method with posthydrothermal treatments at 150 o C for 3 and 12 hours to obtain vertically aligned ZnO nanorods. Nevertheless, the nanorods obtained still needed further improvements.…”

Nanostructural Growth Investigation of ZnO Nanorods Derived from Chemical Bath Deposition for Transparent Heater Application

“…These data are also in agreement with the fact that in the nanometer scale the crystallite size of semiconductor materials strongly affects the Eg. Smaller Eg is obtained with bigger nanocrystallite sizes and thus higher crystallinity, as observed in our previous studies on conventionally annealed and post-hydrothermally treated TiO2 nanoparticles derived from the sol-gel process (Yuwono et al, 2004), TiO2 nanotubes (Yuwono et al, 2011a;Yuwono et al, 2011b), ZnO nanoparticles (Yuwono et al, 2012b), and ZnO nanorods (Sholehah et al, 2013).…”

“…CBD is wellknown as a simple and cheap soft chemical route that runs at low temperature and provides several benefits over other methods e.g., easy control of the process condition, lower energy consumption, and higher yields (Wu et al, 2011). In our previous works we have utilized the CBD process to grow ZnO nanorods on conducting glass substrates and dedicated them for DSSC application (Sholehah et al, 2012;Yuwono et al, 2013;Sholehah et al, 2017). In the current study, we are exploring the potential of ZnO nanorods in a new and important usage, i.e.…”

High Coverage ZnO Nanorods on ITO Substrates via Modified Chemical Bath Deposition (CBD) Method at Low Temperature

“…More specifically, one dimensional (1D) ZnO nanostructure; such as nanorods, nanowires, and nanotubes; has received many attentions due to its wide applications in electronics and optoelectronics area. Various techniques have been developed in order to fabricate vertically align 1D ZnO nanorod, such as radio frequency sputtering [2,3], chemical vapor deposition (CVD) [4], chemical bath deposition (CBD) [5][6][7], and hydrothermal process [8]. CBD is a soft chemical method to grow ZnO nanorods [7].…”