Electrical and optical properties of sol–gel-deposited NiO films and corresponding response to annealing temperature

publication date
October 12, 2023
page number


Rajesh, M., Vengatesan, K., Aly, M.H., Sitharthan, R., Dhanabalan, S.S. and Karthikeyan, M., 2023. Electrical and optical properties of sol–gel-deposited NiO films and corresponding response to annealing temperature. Optical and Quantum Electronics, 55(13), pp.1-17.


The electrical and optical properties of sol–gel deposited nickel oxide (NiO) films are studied as a function of the annealing temperature. NiOX films are successfully obtained by spin coating process on glass and silicon substrates, and their transparency and conductivity have been improved using sol–gel technology. Further, the vibrational, optical, and electrical properties of NiOX film are investigated concerning annealing temperatures between 150 and 450 °C. From the investigation, annealing at 350 °C results in the formation of NiO, and through X-ray Photoelectron Spectroscopy (XPS), it evidences the existence of Ni3 + which is confirmed along with Ni2+ state. Furthermore, when the NiOX samples are treated at 150 °C, their optical transparency in the visible region reaches 90%, and when the temperature is increased to 450 °C, the optical transparency drops to 75–78%. Through investigation, it is also identified that the optical band gaps get reduced to the region of 3.93–3.67 eV through thermal treatments. From the investigation, it is identified that thin films are excellent p-type electrical conductors having a specific resistivity of around 4.8 × 103 Ω/cm. Hence, they can be used in the manufacturing of transparent solar cells such as Hole Transport Layers (HTLs) and wideband semiconductors.


M. Rajesh,  K Vengatesan,  Moustafa H. Aly,  R. Sitharthan,  Shanmuga Sundar Dhanabalan and Madurakavi Karthikeyan

Organisation / Department Address:

  1. Department of Computer Engineering, Sanjivani College of Engineering, Kopargaon, India
  2. College of Engineering and Technology, Arab Academy for Science, Technology and Maritime Transport, Alexandria, Egypt
  3. Centre for Smart Grid Technologies, School of Electrical Engineering, Vellore Institute of Technology, Chennai, India
  4. Functional Materials and Microsystems Research Group, RMIT University, Melbourne, VIC, 3001, Australia
  5. School of Electronics Engineering, Vellore Institute of Technology, Vellore, India