The degree of supersaturation dependent ZnO nano/micro rod arrays thin films growth using chemical bath deposition and hydrothermal methods.

Abstract The growth of one-dimensional (1D) zinc oxide (ZnO) nano/micro rod arrays (N/MRAs) thin films by using a facile, reproducible and cost effective method could be triggering nano/micro morphological structure based devices in the semiconductor technology. Therefore, in this work, the chemical bath deposition (CBD) and hydrothermal (HTM) methods have been used for growing 1D ZnO N/MRAs thin films on ZnO seeded glass substrates. Subsequently, we have studied their fundamental physicochemical properties for determining and distinguishing the growth characteristic of deposition methods. The formation of hexagonal wurtzite crystal structure in the CBD and HTM grown 1D ZnO N/MRAs films has been confirmed by XRD and μ-Raman studies. The intensity of the preferentially oriented diffraction peaks and electron microscopic images depict that the crystallinity, number density and aspect ratio of the 1D ZnO N/MRAs are strongly dependent on level of degree of supersaturation and its changes under deposition method is highlighted here. Further, the size, shape and single crystalline nature of the N/MRAs are strongly confirmed by TEM images and SAED patterns respectively. The photons absorption in the UV region ratify the wide bandgap characteristic of ZnO. Eventually, the presence of localized electron trapping and/or relaxing states in ZnO nuclei layer and in 1D ZnO N/MRAs films are determined from photoluminescence spectra. Graphical abstract Image 1 Highlights • ZnO nano/micro rod arrays thin films were grown by chemical bath deposition and hydrothermal on spray deposited ZnO seeded substrates. • The number density, aspect ratio of the NRs and MRs are strongly depends on the synthetic methods with respect to changing level of degree of supersaturation. • The optical band gap value is found to be 3.18 and 3.15 eV for CBD and hydrothermal grown film respectively. [ABSTRACT FROM AUTHOR]