Effects of Target Composition on the Optical Constants of uC Sputtered ZnO:AI Thin Films

Abstract

AI-doped lJlO thin films were deposited from lnO:AI ceramic and Zn.Al meial alloy targets, Deposition took place in Ar and Ar + O2 atmosphere for lnOAI and ZnAl targets: respectively, using DC magnetron sputtering. Transmittance (T) measurements showed T> SCYl'o in visible region with good NIR shielding, The band gap energy ranged from 3.34 to 3,44 eV and 3.39 to 3.46 eV for films prepared from alloy and ceramic targets, respectively. The films with lowest elecuical sheet resistance of ] 0 0./0 and highest values of mobility and carrier concentration of 159 cm:/V~ and 2.98 x 1021 CI11·3respectively, were obtained using alloy- target at a substrate temperature of 200 "C. However, films prepared from ceramic target at 3 substrate temperature of 300°C revealed the: lowest sheet resistance of 32 D./o: with the highest values of Inability and charge carrier concentration of l-l.] CI1l1;VS and 1.92 x ] 010 cm-] respectively Optical spectra of the films were fitted (0 SCOUT software in order to determine the refractive index, 11 and extinction coefficient. k. Generally, the calculated 11 and k in the visible part of the solar spectrum for different samples; ranged from ].59 (0 2.2 and ()OOO I3 to 0.0 I94 respectively, which are in agreement with results calculated using other methods Key words: DC Magnetron Sputtering, Optical Constants, Transparent Conducting Oxides (TCO)