Lithium and sodium acceptors in ZnO

In earlier investigations it was shown that Li and Na produce deep acceptor states which participate in shallow donor to deep acceptor recombinations in the visible spectral region. We will demonstrate that in the case of group-I elements either incorporated by diffusion or in situ during growth, shallow acceptors are introduced also, having binding energies around 300 meV. The corresponding donor-acceptor pair recombinations have weak electron-phonon coupling.