Electrical properties of Al-doped ZnO films fabricated by a hot-cathode plasma sputtering method

A hot-cathode plasma Sputtering technique Was used to fabricate highly transparent and conducting aluminum-doped zinc oxide (AZO) films oil glass substrates from disk shaped AZO (Al2O3: 5 wt.% and 2 wt.%) targets. Using a target voltage V-T = -200 V and plasma excitation pressure P-Ar = 1.5 x 10(-3) Tort, the lowest resistivity of 4.0 x 10(-4) Omega cm was obtained at 400 nm with a carrier density of 8.7 x 10(20) cm(-3) and a Hall mobility of 17 cm(2)/V s. The analyzed structural properties of these films revealed that this lower resistivity was due to a decrease in the lattice spacing d((0) (0) (2)) of the (0 0 2) plane parallel to the substrate surface. This decrease in lattice spacing was presumably caused by oxygen vacancies acting as an effective source of carrier electrons. (C) 2009 Elsevier B.V. All rights reserved.