Undoped and Li-Doped NiO Coral Reef-like Structures Fabricated using Immersion Method

Abstract

Nickel oxide (NiO) is one of the p-type semiconductors with unique properties suitable for nanosensor applications. It has a wide range band gap and can be fabricated in various methods, leading to different nanostructures and results. In this study, undoped and lithium (Li)-doped NiO were fabricated using the immersion method to investigate their properties. The field emission scanning electron microscopy analysis revealed that both samples produced two layers of nanosheet and nano coral reef-like (CR) structures. X-ray diffraction patterns confirmed the average crystallite sizes for undoped and Li-doped NiO are 24.70 nm and 31.19 nm, respectively. According to ultraviolet-visible spectroscopy, Li-doped NiO has a higher average transmittance percentage of 53% compared to undoped NiO, which has 40%. The estimated optical band gap values are not much different, with 3.94 eV for undoped and 3.95 eV for Li-doped. Electrical measurements also indicated that Li-doped NiO has a higher conductivity value of 7.9 x 10-2 S.m-1, whereas undoped NiO has 7.71 x 10-2 S.m-1.