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

Abstract

(Al, Si)-codoped ZnO powders with a constant molar ratio of Zn:Al (99:1) and various molar ratios of Si:Al (0–0.02) were synthesised by a sol–gel process and characterised 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 Si proportion. The Mo doping resulted in the enhancement of transmittance in the UV–visible light range and the widening of the bandgap. Optimal efficiency appeared at a molar ratio of Si:Al=0.01, and Si doping resulted in the formation of a new emission centre and the enhancement of the emissions in range of visible light.