Effect of VI/II ratio upon photoluminescence and electrical properties of phosphorus-doped ZnTe films grown by metalorganic vapor phase epitaxy

We have investigated photoluminescence and electrical properties of P−doped ZnTe layers grown by metalorganic vapor phase epitaxy as a function of VI/II ratio. Near band-edge emissions are strongly influenced by VI/II ratio. The low VI/II ratio corresponding to Zn-rich condition brings about heavy p-type doping with P as compared to Te-rich condition. The best VI/II ratio for obtaining high quality layer is one. A maximum carrier concentration of 5.4 × 1018 cm−3 is attained even for as-grown ZnTe layer. In this sample, the carrier concentration is almost independent of the measurement temperature, indicating conduction in an impurity band formed by shallow acceptor.