High-density, single-crystal, vertically aligned, Al-doped ZnO nanowires with an Al content of 1.05 atom % were synthesized on ZnO:Ga/glass templates at 550 degrees C. Although introducing Al did not change the physical dimensions of the ZnO nanowires, the lattice constant increased by 0.25% and the optical properties of the ZnO nanowires were degraded. However, the experimental results also showed that the threshold emission field can be significantly decreased from 16 to 10 V/mu m, and the work function, phi, can also be reduced from 5.3 to 3.39 eV by introducing Al atoms into the ZnO nanowires. (c) 2005 The Electrochemical Society.