Electronic structure of ternary CdxZn1−xO (0 ≤ x ≤ 0.075) alloys

Narrowing of the electronic bandgap of ZnO by doping with cadmium opens up further potential uses of the material for photocatalytic applications. However, the mechanism of this important bandgap modification is still unclear. This letter demonstrates that for doped materials, the Fermi level resides within the bandgap in the bulk but lies above the conduction band minimum at the surface of the material, thus producing downward band bending and electron accumulation in the near surface region.