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.