Creating Intermediate Bands in ZnTe via Co-Alloying Approach

We propose an effective co-alloying approach to creating an intermediate band (IB) in bulk ZnTe. First-principles calculations show that a donor-acceptor co-alloying scheme can produce an IB within the band gap of ZnTe and that the position of the IB can be tuned by choosing appropriate donor-acceptor pairs. We find that the position of the IB is governed by the atomic d-orbital energies of dopants, and also by the charge transfer between donor and acceptor atoms and their subsequent intra- and inter-Coulomb interactions. Therefore, the location of the IB can be manipulated by selecting donors and acceptors with desirable d-orbital energies and electronegativities.