Section
Physical Sciences
Abstract
ZnO thin films were deposited using reactive direct current (dc) magnetron sputtering on glass substrates placed at seven variable radial positions (-1, 0, 1, 2, 3, 4 and 5 cm) relative to the sputter-gun (target) axis. A pure zinc target was used and sputtering carried out in argon and oxygen atmosphere with flow rates of 50 sccm and 6 sccm, respectively. XRD characterization showed that, all films crystallized homogeneously in the wurtzite phase with a strong (002) and a weak (004) orientations. Film crystallinity was very low at substrate positions located less than or equal to 1 cm from the target axis but rapidly improved as substrate position increased beyond 1 cm. Film thickness decreased steadily (from 320 to 160 nm) with increase in substrate position from 1 to 5 cm. Film resistivity was much higher (over ~104 Ω cm) at substrate positions located less than 2 cm from the target axis and rapidly decreased with increase in substrate position reaching the order ~10– 3 Ω cm at 3 cm and leveled out. Optical transmittance was homogeneous with 86% in the wavelength range 380 – 2500 nm. Band gap increased dramatically (from 3.15 eV to 3.28 eV) with increase in substrate position.
Recommended Citation
Eneku, John Paul; Otiti, Tom; Mwabora, Julius Mwakondo; and Horwat, David
(2018)
"Effects of Substrate Radial-Position Relative to the Sputter-Gun Axis on the Electrical, Optical and Structural Properties of ZnO Thin Films Deposited by Reactive Direct Current Magnetron Sputtering,"
Tanzania Journal of Science: Vol. 44:
Iss.
4, Article 2.
Available at:https://doi.org/10.65085/2507-7961.1730