Plasma-induced surface textures of ZnO:Al transparent conductive films

Post Ar/H-2 plasma etching method is used to fabricate the texture surface of RF-sputtered ZnO:Al (AZO) transparent conductive films. Different plasma pressures (50 Pa, 100 Pa, 150 Pa and 200 Pa) are adopted during the etching process. The crystallinity improves with increasing the plasma pressure to 150 Pa. Surface morphology varies substantially by the bombardment of high energy Ar and H plasma atoms. Reduction of the mean free path of the plasma atoms and increment of the effective plasma atoms at high pressure will lead to the reduction of RMS after reaching to the largest value of 10.3 nm at 50 Pa. Lowest resistivity of 4.88 x 10(-4) Omega cm and largest carrier concentration of 8.87 x 10(20) cm(-3) are obtained at 50 Pa due to the incorporation of hydrogen donors (passivation defects and grain boundary). The enhanced optical scattering ability by the texture structure (a pit size of similar to 200 nm) results in a largest diffuse transmittance value of 1.68% and a best haze value of 2.00% at 550 nm at 50 Pa. (C) 2014 Elsevier Ltd. All rights reserved.