Enhancement in the optical transmittance of ZnO:Al powders by Mo co-doping

(Al,Mo)-codoped ZnO powders with a constant molar ratio of Zn:Al (99:1) and various molar ratios of Mo:Al (0–0.02) were synthesized by a sol-gel process and characterized by X-ray diffraction, field emission scanning electron microscopy, and UV–vis and luminescent spectrophotometry. The experiments indicated that the powders had random orientation and a slightly larger average particle size that increased with increasing Mo proportion. The Mo doping resulted in the enhancement of transmittance in the UV–visible light range and the widening of the band gap. Optimal efficiency appeared at molar ratio of Mo:Al = 0.01, and Mo doping resulted in the formation of a new emission center and the enhancement of the emissions in range of visible light.