Impact of Radio Frequency Plasma Power on the Structure, Crystallinity, Dislocation Density, and the Energy Band Gap of ZnO Nanostructure

Ahmed F Abdulrahman; Azeez A Barzinjy; Samir M Hamad; Munirah Abdullah Almessiere

doi:10.1021/acsomega.1c04105

Impact of Radio Frequency Plasma Power on the Structure, Crystallinity, Dislocation Density, and the Energy Band Gap of ZnO Nanostructure

ACS Omega. 2021 Nov 17;6(47):31605-31614. doi: 10.1021/acsomega.1c04105. eCollection 2021 Nov 30.

Authors

Ahmed F Abdulrahman¹, Azeez A Barzinjy^{2

3}, Samir M Hamad⁴, Munirah Abdullah Almessiere^{5

6}

Affiliations

¹ Department of Physics, Faculty of Science, University of Zakho, Zakho 42002, Kurdistan Region, Iraq.
² Department of Physics, College of Education, Salahaddin University-Erbil, Erbil 44001, Kurdistan Region, Iraq.
³ Department of Physics Education, Faculty of Education, Tishk International University, Erbil 44001, Kurdistan Region, Iraq.
⁴ Scientific Research Centre, Soran University, Soran-Erbil 44008, Kurdistan Region, Iraq.
⁵ Department of Physics, College of Science, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, 31441 Dammam, Saudi Arabia.
⁶ Department of Biophysics, Institute for Research and Medical Consultation (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, 31441 Dammam, Saudi Arabia.

Abstract

The aim of this study is to investigate the effect of radio frequency (RF) plasma power on the morphology, crystal structure, elemental chemical composition, and optical properties of ZnO nanostructure using a direct current magnetron sputtering technique. This study emphasized that the growth rate and surface morphology of the polycrystalline ZnO were enhanced as the radio frequency (RF) plasma power increased. This can be observed by fixing other parameters such as the growth time, substrate temperature, and chamber partial pressure. The RF plasma power alteration from 150 to 300 W can produce uniform nanograin, spheroid, and nanorods. Additionally, the RF plasma power alteration leads to the alteration in the ZnO nanorod diameter from 14 to 202 nm. It was observed that the XRD intensities are increased at higher plasma powers. This, perhaps, can be inferred from the transformation of the granular microcrystals to the needlelike or platelike large crystals, as already examined using SEM images. This also has an impact on the average crystalline size, which increased from 10 to 40 nm on increasing the RF plasma power. Moreover, the increase of the RF plasma power has an obvious impact upon the optical band-gap energy, which was accordingly decreased from 3.26 to 3.22 eV. Finally, the absorption band edge was shifted to a lower-energy region due to the quantum size effect at the nanorange.