Characterisation under hydrostatic pressure of narrow-gap Hg1-xCdxTe and Hg1-xZnxTe

Abstract

The authors have performed transport experiments under hydrostatic pressure on samples of two different narrow-gap mercury telluride mixed compounds: Hg1-xCdxTe (x=0.27, 0.28, 0.30) and Hg1-xZnxTe (x=0.15). The investigated samples of HgCdTe are n-type samples grown by the molecular beam epitaxy technique on GaAs/CdTe substrates and doped with In during the growth. The experiments, performed at liquid helium temperature in the magnetic field range B=0-5 T and under hydrostatic pressure up to P=11 kbar, allow them to conclude that this doping process does not induce any resonant impurity level as previously observed for boron-implanted samples. They used the same experimental techniques (0<B<19 T, 0<P<9 kbar, 1.68<T<300 K) to study HgZnTe samples grown by the travelling heating method. This open-gap material (x=0.15) is a high-mobility semiconductor (n=6.8*1014 cm-3 and mu =1.8*106 cm2 V-1 s-1). Nevertheless, its pressure behaviour in zero magnetic field and in the high-magnetic-field regime shows the existence of two impurity levels.