Vertically aligned aluminum-doped ZnO (AlZnO) nanorods with controllable Al concentration were grown on ZnO films through catalyst-free vapor phase deposition. X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and photoluminescence were used to characterize the structural and optical properties of the obtained nanorods array. The aluminum doping concentration can be controlled simply by adjusting the distance between the source material and the substrates. Through photoluminescence measurements, we find out that the intensity of green band reduces as the aluminum doping concentration increases, and the origin of this phenomenon is discussed. (c) 2007 Elsevier B.V. All rights reserved.