  Metal sulfides are emerging as an important class of materials for
photocatalytic applications, because of their high photo responsive nature in
the wide visible light range. CdS in this class of materials, have a direct
band gap of 2.4 eV, have gained special attention due to the relative position
of its conduction band minimum, which is very close to the energies of the
reduced protons. However, the photogenerated holes in the valence band of CdS
are prone to oxidation and destroy its structure during photocatalysis. Thus
constructing a CdS based heterostructure would be an effective strategy for
improving the photocatalytic performance. In this work we have done a detail
theoretical investigation based on hybrid density functional theory calculation
to get insight into the energy band structure, mobility and charge transfer
across the CdS/CdSe heterojunction. The results indicate that CdS/CdSe forms
type-II heterostructure that has several advantages in improving the
photocatalytic efficiency under visible light irradiation.
