The Effect of Post-Growth Annealing on the Physical Properties of Fe-Doped ZnO Nanostructure

Abstract

The synthesis of nanostructure materials for optoelectronic and photonic devices is often scrutinized. Due to its reasonable and environmentally benign nature, ZnO, a semiconductor, is well regarded for its potential to develop photonic devices. In this respect, low-temperature aqueous chemical growth is used to create ZnO nanostructures doped with Fe. The temperature-dependent change in the Fe-doped ZnO nanostructure was seen in the XRD spectra at larger angles (200°C, 400°C, 600°C). It was shown that the crystalline size of as-grown Fe-doped ZnO nanostructures grows in correlation with a reduction in the d-spacing value. Furthermore, U-V visible spectroscopy measurements are conducted for all the synthesized samples. It is also observed from the U-V visible spectroscopy measurements that the energy band gap of the Fe-doped ZnO decreases by increasing the Fe concentration. We investigate the influence of post-growth annealing on the energy gap of the sample with 5% Fe content and find that increasing the temperature reduces the energy gap. The SEM results revealed that hexagonal rods like nanostructure are successfully synthesized for pure ZnO whereas no morphological change occurred for Fe doped ZnO. Moreover, the destroyed surface after annealing was identified inside the SEM particles. This research will help to develop LEDs due to decrease in band gap.