In the study, we present the electrical and optical properties of zirconium-doped zinc oxide (ZnO:Zr) thin films grown by atomic layer deposition (ALD) on sapphire substrates. The ZnO:Zr films exhibited low resistivity (1.3 x 10(-3) Omega cm), high carrier concentration (2.2 x 10(20) cm(-3)), and high transparency (> 92%) in the visible spectrum. The photoluminescence spectra consisted of a strong spontaneous emission at 380 nm associated with the near-band-edge emission and a weak defect-related band. Optically-pumped stimulated emission in ZnO:Zr films was achieved with a low threshold intensity of 105 kW/cm(2) at room temperature. The results indicate that the ZnO:Zr films prepared by ALD are applicable to transparent conductive oxide and ultraviolet light-emitting materials. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3575161] All rights reserved.