Electrical Properties of DC Reactive Magnetron Sputtered ZnO:Al Films from Optical Spectra

Authors

PD Nsimama, Department of Science and Laboratory Technology, Dar Es Salaam Institute of Technology, P.O. Box 2958, Dar Es Salaam, TanzaniaFollow
ME Samiji, Physics Department, University of Dar Es Salaam, Tanzania, P.O. Box 35063, Dar Es Salaam, TanzaniaFollow

Section

Physical Sciences

Abstract

Reactive direct current (DC) sputtered ZnO:Al films were prepared using the plasma emission monitoring (PEM) system. Films were deposited using PEM setpoints ranging from 50 to 80%. Transmittance and reflectance of the films were measured by using the UV-VIS-NIR Lambda 900 double beam spectrophotometer. The sheet resistance was measured using the four-point probe. Films optical spectra were fitted with the Drude model to determine their charge carrier concentration, mobility and the alternating current (AC) resistivity. The highest values of mobility and charge carrier concentration were 8.31cm2/Vs and 2.14 x 1021cm-3 respectively. The lowest value of the AC resistivity was given by the ZnO:Al film with the highest value of the product (Nμ) of charge carrier concentration (N) and mobility (μ). The DC and AC resistivity were of the same orders of magnitude. The optical bandgap was found to increase with the increase in charge carrier concentration. A linear variation of N2/3 with the optical bandgap, which concurs with theBurstein-Moss shift theory, was obtained.

Recommended Citation

Nsimama, PD and Samiji, ME (2012) "Electrical Properties of DC Reactive Magnetron Sputtered ZnO:Al Films from Optical Spectra," Tanzania Journal of Science: Vol. 38: Iss. 2, Article 3.
Available at:https://doi.org/10.65085/2507-7961.1855