Carrier concentration enhancement of p-type ZnSe and ZnS by codoping with active nitrogen and tellurium by using a δ-doping technique

We have studied the p-type doping of ZnSe and ZnS grown by molecular beam epitaxy using active nitrogen and tellurium. Highly conductive p-type ZnSe and ZnS films have been achieved by inserting heavily N-doped ZnTe layers into each layer. A hole concentration of 7×1018 cm−3 in a ZnSe/ZnTe:N δ-doped layer and a [Na-Nd] value of 5×1017 cm−3 in a ZnS/ZnTe:N δ-doped layer were obtained. Excitonic emission associated with the N acceptor at 2.792 eV in ZnSe was dominant in the photoluminescence spectra at 14 K and the emission related to the Te isoelectronic deep centers was negligibly weak. These results indicate that the incorporation of ZnTe:N single layers by this δ-doping method dramatically increases the hole concentration, and the optical properties are consistent with this improvement.