p-type doping with N and Li acceptors of ZnS grown by metalorganic vapor phase epitaxy

ZnS layers were grown by metalorganic vapor phase epitaxy on GaAs substrates using diethylzinc, ditertiarybutyl sulphide, and triallylamine as organometallic sources. After postgrowth rapid thermal annealing, the ZnS layers showed p-type conductivity with hole concentrations up to ${10}^{18} {\mathrm{cm}}^{\mathrm{-3}}.$ Photoluminescence measurements gave additional indications of the presence of electrically active nitrogen acceptors. In separate experiments, lithium was diffused from a LiH solid source into ZnS layers grown without the nitrogen precursor. High-conductivity p-type material was directly obtained with no need of thermal anneal.