Transport Properties of Shallow InAs Quantum Wells for Spintronic Applications

Spintronic applications of heterostructures require materials with excellent semiconducting properties, strong spin-orbit coupling, and shallow channels for optimized injection and detection of currents. To this goal, shallow n-type InAlSb/InAs/AlGaSb quantum wells have been fabricated in Hall bars followed by measurements of their sheet resistance in variable magnetic field, temperature, and under variable illumination conditions, with wavelengths of 400 nm up to 1300 nm. Here we used analysis of the Shubnikov-de Haas oscillations and the Hall effect in order to find the semiconducting and spin-orbit properties of these structures. The results were compared and contrasted with the properties of deep channel InAs/InGaAs with excellent spin-orbit coupling properties. We find that the carrier concentration of the shallow channels increases under infrared illumination, but decreases when further decreasing the wavelength. Parameters including the effective mass, the quantum scattering time, and the spin-orbit coupling are extracted and their dependence on the carrier concentration and the type of structure is discussed.