Antimony-doped ZnSe grown by molecular-beam epitaxy

Abstract

Antimony-doped ZnSe layers were grown by molecular-beam epitaxy (MBE) on (100) GaAs substrates using a variety of antimony oven temperatures in the range of 550–800 °C and substrate temperatures in the range of 250–330 °C. Sb concentrations as high as mid-1019 cm−3 were measured in the ZnSe layers by the secondary ion mass spectrometry technique, although an Sb concentration limit of ≤1019 cm−3 was established in this work for the growth of single-crystal Sb-doped material. The Sb incorporation coefficient in ZnSe was found to depend strongly on substrate temperature, increasing from ∼10−2 at 330 °C to ∼1 at 250 °C. In addition, a strong dependence was found of the ZnSe lattice parameters measured normal to the heterointerface on Sb concentration in the layers, the lattice parameter increasing monotonically with increasing Sb concentration. Acceptor bound excitonic emission was not detected from the Sb-doped ZnSe layers by 4.2-K photoluminescence analysis, indicating that Sb incorporation under the MBE growth conditions did not produce a shallow acceptor level in the ZnSe band gap.