The effect of Co-doping on dielectric properties and bandgap of zinc silicate nanowires

In this study, pristine and cobalt (Co) doped zinc silicate (Zn2SiO4) nanowires were synthesized by a simple and cost-effective hydrothermal method. The average length and diameter of Zn2SiO4 nanowires were 1.0–1.5 μm and 40–60 nm, respectively, in electron microscopic studies. In the case of Co-doped Zn2SiO4 nanowires, average length and diameter increase to 4.0–5.0 μm and 70–90 nm, respectively, and a significant increase in particle size was observed. A dielectric constant measurement of pristine and Co-doped Zn2SiO4 nanowires was performed in the frequency range of 20 Hz–2 MHz. The dielectric constant of pristine and Co-doped Zn2SiO4 nanowires was found to be 212 and 1360 at a frequency of 20 Hz, respectively. Such dramatic enhancement in the dielectric constant (approximately six fold) of Co-doped Zn2SiO4 nanowires suggests that these nanowires are promising materials for applications in next generation charge storage devices. UV–Vis spectral analysis shows a remarkable reduction in the optical bandgap of Co-doped Zn2SiO4 nanowires as a result of doping. Such enhancement in the dielectric constant and reduction in the optical bandgap were discussed in light of doping and size enhancement.