Argon gas pressure dependence of the properties of transparent conducting ZnO : Al films deposited on glass substrates

Aluminium doped zinc oxide (ZnO:AI) films were deposited on amorphous subst rates heated up to 200 degreesC with a radio frequency (rf) power of 100 W by rf magnetron sputtering from a ZnO target mixed with Al2O3 Of 2 Wt.%. Ar gon gas pressure during deposition was in the range 0.08-2.7 Pa. As argon g as pressure was increased, the deposition rate and the grain size were decr eased and the surface roughness was increased. Furthermore, the carrier con centration and the Hall mobility were decreased and thus the electrical res istivity was increased. However, the optical transmittance of about 90% was maintained over the argon pressure range. The resistivity of the film depo sited at argon gas pressure of 0.13 Pa was about 2.5 x 10(-4)Ohm cm, a valu e comparable to that for indium tin oxide film presently used as a transpar ent electrode. (C) 2001 Elsevier Science B.V. All rights reserved.