Nitrogen Plasma Doping during Metalorganic Chemical Vapor Deposition of ZnSe

Active nitrogen generated by low-frequency high-voltage plasma discharge was used at pressures on the order of 1 Torr. Using a technique of alternate growth and plasma doping, high-quality N-doped ZnSe layers were grown on GaAs(100) substrates. In the low-temperature photoluminescence (PL) spectra, the narrow and distinct peak for acceptor-bound exciton, together with donor-acceptor pair peaks is predominant, which suggests N-acceptor doping on the order of 1018 cm-3. The strong PL intensity indicated that the layers were free from plasma damage. The successful doping at the relatively high pressures strongly suggests that the metastable state ( A3 Σ u +) of a nitrogen molecule is responsible for the N doping. Although as-grown layers are highly resistive, they are converted to p-type layers with a hole concentration of ∼1×1015 cm-3 upon rapid thermal annealing at 700° C.