Far-infrared determination of effective mass and valence-band offset in the HgTe/CdTe superlattice

We have analyzed far-infrared plasma effects in two HgTe/CdTe superlattices to give effective masses parallel to the planes. The results at 78 and 300 K, respectively, are m*/m₀=0.010 and 0.022 for dHgTe/dCdTe =(80 A{})/(40{}), and 0.013 and 0.044 for dHgTe/dCdTe =(64 A{})/(60{}). The masses for the (80 A{})/(40 A{}) superlattice agree with those for alloy Hg_1-x{Cd}ₓ$Te with the same band gap, and yield a valence-band offset of 300 meV when compared with theory. Our analysis also gives layer thicknesses, and Hg content in the nominal CdTe barrier layers.