Optical properties of ZnO nanorods derived from chemical bath deposition process with different seeds solution concentration

Abstract

Owing to their high surface to volume ratio and fast electron transfer, zinc oxide (ZnO) nanorods have been well-known as potential nanostructured material for various applications including sensors, dye sensitized solar cells, optoelectronic, transparent heater and biomedical devices. Among other synthesizing techniques for obtaining ZnO nanorods, chemical bath deposition (CBD) has been thought as a simple and low-cost method. However, there are several processing parameters that need to be investigated for the above-mentioned applications where the highly optical transparency of thin film ZnO nanorods grown on glass substrates is one of important targets to be achieved. In this work, ZnO nanorods were synthesized through CBD process at low temperature (0°C) by using seed solution prepared by dissolving 1: 1 equimolar zinc nitrate tetrahydrate and hexamethylene tetraamine. For investigation purposes, three different concentration of seed solutions i.e. 0.005, 0.025 and 0.05 M were used. Thin films containing ZnO nanoseeds were formed by spin coating the precursors on the glass substrates, followed with annealing at 2000C for 5 minutes. Finally, the ZnO nanorods were further grown at 90ºC for 3 hours in the beaker glass using the same solution. Xray diffraction (XRD) analysis showed that all ZnO nanorods demonstrated a strong (002) peak belong to wurtzite phase. It was found that the estimated crystallite size and band gap energy (Eg ) for ZnO nanorods derived from the seed solutions of 0.005, 0.025 and 0.05 M were 21.42, 137.11, 171.39 nm, and 3.60, 3.20, 3.18 eV, respectively. However, the optical transparency was adversely lowered from about 75 to 40 % as a result of increased coverage of ZnO nanorods on the glass substrate. For transparent heater application where, a desired combination of high optical transparency and suitable electronic properties is needed, the current results were considered to be promising.

Template-free chemical deposition of highly crystalline ZnO nanorod thin films

“…Also, it must be noted that the commercial grade ZnO nanoparticles used as seeds are also polycrystalline in nature, implying the different orientations of crystallite grains. On the other hand, films synthesized using chemical bath deposition 21 and sol–gel methods 19 reported in the literature show that the intensity is particularly high for the peak (002) while the intensities of all other peaks in the diffraction pattern are relatively low. In these published reports, the nanorods exhibit a preferred direction of growth.…”

“…Besides, the role of a seed layer grown using simple drop-casting of ZnO nanoparticle dispersions in controlling the growth of ZnO nanostructured films with nanorod morphology has also been investigated here. A similar study conducted to investigate the effects of seed-controlled nucleation and growth using chemical bath deposition has been reported by Suhaimi et al 21 The ZnO seed layer was grown on Si and quartz substrates by drop-casting a highly dilute and stable suspension of ZnO nanoparticles. The synthesized ZnO nanorods in both powder and film forms were characterized to study their structure, morphology, composition, optical absorption and fluorescence emission properties.…”

“…Deposition of ZnO thin films has been accomplished by a variety of physical and chemical methods including thermal evaporation, 13 sputtering, 14 chemical vapor deposition (CVD), 15 pulsed laser deposition, 16 spray pyrolysis 17 electrochemical methods, 18 the sol–gel method 19,20 and chemical bath deposition. 21 Sputtering, pulsed laser deposition, and chemical vapor deposition techniques are expensive in view of the basic requirement of specialized, vacuum-based deposition equipment. In contrast, chemical bath deposition is a simple and cost-effective process for the production of large area uniform nanostructured thin films.…”

Study of The Electrical, Optical and Morphological Properties in Submicron and Microstructured ZnO Thin Films Obtained by Spin Coating and Chemical Bath Deposition

“…Among these, some of the most common are Spin Coating and Chemical Bath Deposition. There are works that report the growth of micro and nano ZnO bars on bu ers deposited by Spin Coating using Chemical Bath Deposition (Chen and Ting, 2016;Wu et al, 2010;Rana et al, 2017;Suhaimi and Yuwono, 2019;Chang et al, 2017), that is, using a process that involves these two techniques. The virtue of employing this process is that it allows growing micro/nano ZnO bars aligned and oriented (Chang et al, 2017) .…”