Behavior of arsenic in ZnSe grown by a closed Bridgman method

High-quality and large-size ZnSe single crystals doped with arsenic (As) have been grown by a closed Bridgman method. Photoluminescence (PL) spectra show bound exciton emission related to As acceptors and strong donor acceptor pair (DAP) emissions in all As-doped ZnSe. When the doping concentration reaches 5 × 1018 cm− 3, two sets of DAPs, namely shallow-DAP (DsAP) and deep-DAP (DdAP), are observed. This indicates that As behaves both as a shallow acceptor and a deep complex donor. By examining excitation intensity dependences of the DAP emissions, the ionization energy of As as a shallow acceptor is estimated to be 108 ± 1 meV, and that of the deep complex donor related to As to be 36 ± 1 meV. Furthermore, the correlations between localization energy and corresponding ionization energy for some acceptors are summarized. The results indicate that these correlations obey Haynes’ rule very well.