The impact of green synthesized seed layer on ZnO nanorod arrays grown by chemical bath deposition

ZnO nanorods were synthesized via CBD method on a seed layer coated substrate. Prior to growth, a glass substrate was seeded with the biosynthesized ZnO nanoparticles using Thymus Kotschyanus extract. XRD confirmed that for the sample within higher precursor concentration, the (100) peak is noticeably shorter, and the majority of the nanorods are grown in the (002) plane, indicating crystal growth are along the c-axis. However, the nanorods are mostly aligned along the (100), (002), and (101) planes for samples at 0.02 and 0.05 Mol precursor concentrations. The presence of ZnO nanorods within hexagonal-wurtzite structure, is favored orientation along the c-axis. As the precursor concentrations of the seed layer increased from 0.02 to 0.1 Mol, the dispersion of ZnO nanoparticles became denser, the maximum absorption peaks red-shifted, from 395 to 420 nm, and the bandgap energy of the biosynthesized ZnO decreased from 3.59 to 3.38 eV, with increasing precursor concentrations. Graphical abstract