Electrical measurements of molecular-beam epitaxy HgTe–CdTe superlattices and absorption coefficient analysis of molecular-beam epitaxy HgTe

Abstract

Transport properties of molecular-beam epitaxy (MBE) grown HgTe and HgTe–CdTe superlattices on (112) CdTe substrates and the absorption coefficient for MBE HgTe are measured. The Hall and optical data for HgTe agree with a Kane-type band-structure model with parameters appropriate for HgTe. The Hall data for the HgTe–CdTe superlattices indicate that the superlattices are p-type with an n–p transition temperature which can be used to determine the band gap. The Hall data are modeled fairly well using simple band-structure calculations. Measurements of the Shubnikov–de Haas effect indicate that light-hole-like carriers (m*∼0.01 m0) exist in the p-type conduction range of these samples. This is in disagreement with the Hall data which suggest that the predominate carriers in this conduction range are heavy holes (m*∼0.4 m0).