HgCdTe quantum wells grown by molecular beam epitaxy

CdxHg1-xTe-based (x = 0 - 0.25) quantum wells (QWs) of 8 - 22 nm in thickness were grown on (013) CdTe/ZnTe/GaAs substrates by molecular beam epitaxy. The composition and thickness (d) of wide-gap layers (spacers) were x ∼ 0.7 mol.frac. and d ∼ 35 nm, respectively, at both sides of the quantum well. The thickness and composition of epilayers during the growth were controlled by ellipsometry in situ. It was shown that the accuracy of thickness and composition were ∆x = ± 0.002, ∆d = ± 0.5 nm. The central part of spacers (10 nm thick) was doped by indium up to a carrier concentration of ∼10 15 cm −3 . A CdTe cap layer 40 nm in thickness was grown to protect QW. The compositions of the spacer and QWs were determined by measuring the Е1 and Е1+∆1 peaks in reflection spectra using layer-by-layer chemical etching. The galvano- magnetic investigations (the range of magnetic fields was 0 - 13 T) of the grown QW showed the presence of a 2D electron gas in all the samples. The 2D electron mobility µe = (2.4 - 3.5)×10 5 cm 2 /(V·s) for the concentrations N = (1.5 - 3)×10 11 cm −2 (x < 0.11) that confirms a high quality of the grown QWs.