Effect of temperature in bands structure, effective mass and correlation with magneto-transport properties in a nanostructure far-infrared detector superlattice

Abstract

We report here the effect of temperature in bands structure performed in the envelope function formalism, effective mass and magneto- transport properties of n-type HgTe (d(1)=8.6 nm) /CdTe (d(2)=3.2 nm) superlattices (SLs). When d(2) increase the gap E-g(Gamma) decrease to zero, at the transition semiconductor to semimetal conductivity, and become negative accusing a semimetallic conduction after the point T'(d(2)T', ET'). d(2)T' and ET' increases with temperature and removes the transition to higher d(2). Eg(Gamma) increases from 48 meV at 4.2 K to 105 meV at 300K. The Fermi level is constant (E-F(2D) approximate to 90 meV) until 77K and increases to 167 meV at 300K. Our Theoretical calculations have provided good agreement with the experimental data. The formalism used here predicts that the system is semiconductor for our ratio d(1)/d(2) = 2.69, when d(2) < 100 nm. In our case, d(2)=3.2 nm and E-g (Gamma,77K) = 60 meV so this sample is a two-dimensional far-infrared detector semiconductor (12 mu m<lambda(c)<28 mu m).