We zone-engineered HgCdTe/HgTe/HgCdTe quantum wells (QWs) using the molecular-beam epitaxy (MBE) method with in situ high-precision ellipsometric control of composition and thickness. The variations of ellipsometric parameters in the w-D plane were represented by smooth broken curves during HgTe QW growth with abrupt composition changes. The form of the spiral fragments and their extensions from fracture to fracture revealed the growing layer composition and its thickness. Single and multiple (up to 30) Cd x Hg 1Àx Te/HgTe/Cd x Hg 1Àx Te QWs with abrupt changes of composition were grown reproducibly on (013) GaAs substrates. HgTe thickness was in the range of 16 nm to 22 nm, with the central portion of Cd x Hg 1Àx Te spacers doped by In to a concentration of 10 14 cm À3 to 10 17 cm À3 . Based on this research, high-quality (013)-grown HgTe QW structures can be used for all-electric detection of radiation ellipticity in a wide spectral range, from far-infrared (terahertz radiation) to mid-infrared wavelengths. Detection was demonstrated for various low-power continuous-wave (CW) lasers and high-power THz pulsed laser systems.

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Ion milling was used to establish the minimum donor doping level N md required for obtaining n-regions with reproducible electron concentration in HgCdTe-based LWIR and MWIR device structures fabricated with ion treatment. The experiments were performed on n-type films grown by molecular beam epitaxy, un-doped and in situ doped with indium with the concentration N In = 5 × 10 14 -10 17 cm −3 . A study of the electrical properties of the milled films showed that N md comprised ∼2 × 10 15 cm −3 for the LWIR and ∼5 × 10 15 cm −3 for the MWIR films. In the films with N In exceeding these critical values, the electron concentration after the milling strictly followed the doping. A need for consideration of the disintegration of the milling-induced defects is also shown.

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