Impact of the microwave power on the structural and optical properties of nanocrystalline nickel oxide thin films

• Main Authors: Ansari, Akhalakur Rahman, Rajput, Umair Ahmed, Imran, Mohd, Shariq, Mohammad, Abdel-wahab, M. Sh, Hammad, Ahmed H.
• Format: Article
• Published: Springer 2021
• Subjects: Q Science (General); QC Physics
• Online Access: http://eprints.um.edu.my/28326/
• Institution: Universiti Malaya

Nanocrystalline nickel oxide thin films were prepared by combined techniques of direct current sputtering (DC sputtering) and microwave plasma chemical vapor deposition to perform high-quality films. The prepared films were subjected to three different microwave powers at 400, 800, and 1200 W. The structural and morphological properties of the prepared films were investigated by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). The prepared films have a trigonal structure. The crystallite size was calculated from Scherer's formula and uniform dimensional model (UDM). The calculated size increased from 213 to 241 angstrom as the microwave power increases from 400 to 1200 W, respectively. The lattice strain was also calculated from UDM model, and it had a lower value of 1.8 x 10(-3) at 800 W. The optical properties such as transmittance, reflectance, absorption coefficient, extinction coefficient, and the dispersion were investigated. The optical transition of such films was direct transition, and the optical band gap values were observed to decrease from 3.950 to 3.367 eV as the microwave power increase from 400 to 1200 W, respectively. The refractive index and the dispersion energy parameters were studied in detail, and the static and lattice dielectric constant were deduced.