Pair spectra in copper-doped zinc telluride

The first observation of discrete donor-acceptor pair lines in copper-doped ZnTe is reported. The spectral analysis shows that the two impurities are located on the same sublattice (type-I spectrum) and gives EACu+ED=168±1 meV and ε9.15. The binding energy of the acceptor is obtained from the $n=2$ orbital states with even and odd parity evidenced from photoexcitation spectra and resonant luminescence of distant pairs. It is deduced that EACu149 meV, ED19 meV, confirming that the dominant acceptors in ZnTe are Cu atoms on Zn sites and giving direct information on the site occupied by the unidentified shallow donor (s) in this material.