Abstract
Transparent Al-doped ZnO (AZO) conductive films were prepared by confocal dc-reactive magnetron sputtering using Zn and Al targets in an Ar/O 2 reactive atmosphere. The effect of Al substitution on the near-field radio-frequency (RF) noise absorption of the AZO films was investigated. After a standard short-open-load-through calibration, the near-field RF noise attenuation was measured using a RF microstrip test fixture suitable for quasi-transverse electromagnetic wave propagation. The RF noise absorption capability of the AZO films is enhanced from essentially zero to 26% (4-6 GHz) by doping with 5.9% Al. Surface proximity-induced loss is considered the dominating mechanism in the RF noise absorption of AZO films. The crystal quality and morphology are affected significantly by the substitution of Al in AZO films. Dc conductivities, dielectric properties and optical characterizations are also discussed. © 2010 IOP Publishing Ltd.