Band gap narrowing of CdO powder by rare earth neodymium doping

Rare earth Nd-doped CdO powders with various Nd contents (0-2.0 at.%) were synthesized by a coprecipitation process and characterized by X-ray diffraction, field emission scanning electron microscopy, and UV-vis spectrophotometry. The experimental results indicate that the Nd doping led to a decrease of the average particle size and a change of thenoptical property. The band gap of the CdO powder was suddenly narrowed about 12.45% due to a slight Nd doping of 0.5 at.% and then increased with further increasing Nd content. This variation was explained by the available band gap narrowing models.