Journal of the Korean Physical Society

pISSN 0374-4884 eISSN 1976-8524


J. Korean Phy. Soc. 2006; 49(9(7)): 584

Published online December 20, 2006

Copyright © The Korean Physical Society.

Deposition-Temperature Effects on AZO Thin Films Prepared by RF Magnetron Sputtering and Their Physical Properties

Jeung Hun Park, Jong Moon Shin, Su-Young Cha, Jin Woo Park, Se-Young Jeong, Hyuk K. Pak and Chae-Ryung Cho


Transparent conductive thin films have attracted much attention due to their high conductivity and transmittance. In this paper, in order to find the optimal condition for fabricating opto-electronic devices, we investigated aluminum-doped zinc oxide (AZO) thin films prepared by radio-frequency (RF) magnetron sputtering on glass substrates by using a 2 wt.$\%$ of Al-doped ZnO target as a function of deposition temperature. The structural, electrical, and optical properties of AZO thin films were studied in terms of the deposition temperature. The crystal structure of AZO thin films had a hexagonal wurtzite structure and the orientation of the sample was along the $c$-axis, regardless of deposition temperature. The deposition temperature had influence on the average grain size and surface roughness, which could be confirmed by means of SEM and AFM. The average grain size increased with increasing deposition temperature. After increasing the deposition temperature, the surface of the AZO thin film improved but the root-mean-square (RMS) value of the surface roughness slightly increased. Also, the average transmittance of AZO thin films in the visible range (400 $sim$ 800 nm) was above 90 $\%$. The optical band gap was dependent on the deposition temperature, and the value of the band gap of AZO thin films increased with increasing deposition temperature. The experimental results showed that the electrical resistivity of the AZO films deposited at room temperature (RT) and at 500 $^{circ}$C were 8.046 $ imes$ $10^{-4}$ $Omega$-cm and 1.297 $ imes$ $10^{-4}$ $Omega$-cm, respectively. Based on this work, we can find the best physical conditions of AZO thin films. Therefore, fabricated AZO thin films can be applied to transparent electrodes of OLEDs.

Keywords: AZO, ZnO, Al-doped ZnO, RF magnetron sputtering, Transparent electrode