Properties of nanostructured ZnO thin films synthesized using a modified aqueous chemical growth method

Abstract

Research and development of nano-sized Zinc Oxide (ZnO) has recently received great attention due to its remarkable properties such as large exciton binding energy of 60 meV, extraordinary photosensitivity, nontoxic nature, wide bandgap and the fact that it is a low cost material with many technological applications. The inherent necessity for stoichiometric ZnO nanostructures suggest that a deposition method where the film stoichiometry is controlled by a chemical reaction is unavoidable. Moreover, it is extremely important, when developing new methods for deposition of ZnO nanostructures to keep the deposition system as simple as possible, maximize throughput, and keep costs at a minimum. Modified aqueous chemical growth method offer such an opportunity. In this work, ZnO nano-petals on microscope glass substrates have been prepared by using a modified aqueous chemical growth method. On the other hand, before utilization of the fabricated ZnO nanostructures by any technique for any technological applications, it is essential to investigate morphological, optical, electrical and structural properties. In this work morphological, optical, electrical and structural properties with respect to change in deposition time have been cross examined using FESEM, UV-Vis spectroscopy, I-V properties by Keithley system and XRD respectively. SEM micrographs have revealed very little changes in the shape, orientations and distribution of ZnO nanopetals formed with change in deposition times. SEM micrographs have also revealed the growth pattern for the prepared ZnO nano-petals which proceeds via a nucleation, and coalescence of ZnO nuclei. XRD analysis have revealed that the synthesized ZnO nano-petals have a hexagonal Wurtzite ZnO structure with peaks at 2θ positions 31.7°, 34.4°, 36.2°, 47.4°, 56.5°and 62.7° belonging to the (100), (002), (101), (102), (110) and (103) planes respectively. UV-Vis spectroscopy has in the same way shown that the synthesized ZnO nano-petals have energy band gaps ranging from 3.46 eV to 3.65 eV. I-V measurements have disclosed that the ZnO nano-petals are conductive. Film resistivity values obtained from the I-V curves showed an exponential increase in resistivity with increased film thickness. Our method of preparation of ZnO nano-petals via a chemical assisted route can serve as benchmark for controlled synthesis of ZnO nanostructures for various technological applications.

Effect of Substrate Temperature on Photoelectric Properties of AZO Thin Films

“…Zinc oxide (ZnO) has the characteristics of low cost, abundant content in nature, wide bandgap (3.37 eV), high absorption in UV region, nontoxicity, high exciton binding energy, and high mobility. [7,8] Its excellent electronic, optical, magnetic, and chemical properties have potential device applications in various fields of sensors, light-emitting diodes (LED), thin-film transistors (TFT), clear and flexible displays, piezoelectric nanogenerators, and solar cells, [9][10][11][12] becoming the most promising materials in the II-VI group of oxides. Intrinsic ZnO is an insulator, which often has disadvantages such as high resistivity and poor stability, making it unable to be directly applied to optoelectronic devices.…”

Fabrication of Nanostructured Cadmium Selenide Thin Films for Optoelectronics Applications

“…This observation suggests that 80°C is the ideal bath temperature in which nucleation and growth of Cd and Se ions on the substrates can proceed favorably to form nanoparticles. Once the initial nuclei are attached on the substrate, further growth from the impinging ions in the condensation is expected to proceed via the Volmer-Weber growth pattern, leading to the observed increase in both the density and size of the nanoparticles (Apeh et al, 2019 ).…”

Effect of annealing temperature on structural, optical, and photocatalytic properties of modified sol–gel‐driven ZnO nanoparticles

“…ZnO NPs have proven to be vital in photonics, optoelectronics, sensors, spintronics, and antibacterial applications as well 3 . Various synthesizing routes resulting in different morphologies have been explored by different researchers 4–7 . Among different synthesizing methods, the modified sol–gel route offers more flexibility, cheaper production costs, reduced operating temperatures, and controlled molecular homogeneity of the NPs 8 .…”