Low-temperature transport properties in AlxGa1-xAsySb1-y /InAs quantum wells : Well-width dependence

• Published in: Journal of crystal growth 2007-04, Vol.301-302, p.199-202
• Main Authors: ISHIDA, S, FUJIMOTO, A, ARAKI, M, OTO, K, OKAMOTO, A, SHIBASAKI, I
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Materials science; Nanoscale materials and structures: fabrication and characterization; Other semiconductors; Other topics in nanoscale materials and structures; Physics; Quantum wells; Specific materials; Surface and interface electron states
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2006.11.263

Low-temperature magneto-transport properties of AlxGa1-xAsySb1-y/InAs deep quantum wells (QWs) with different well widths (Lw=15-500nm) and their dimensionality were studied. The Hall data were analyzed by means of the two-carrier model: coexistence of electrons and holes for Lw=15-150nm and existence of two types of electrons with different mobility for Lw=300 and 500nm. The profile of perpendicular magnetoresistance (MR), rhoxx(B) for the two-dimensional electrons (2DEs) in narrow QWs (Lw=15 and 50nm) can be divided into the following four regimes: (1) the negative MR due to the weak localization (WL) in extremely low B-fields, (2) the crossing of rhoxx for different temperatures at Bc=1/mue in moderate B-fields due to the orbital effect on the electron-electron interaction, (3) the Shubnikov-de Haas oscillations and (4) the quantum Hall effect in high-B fields. As for the in-plane MR except in the very low-field region characterized by the WL, Deltarhoxx(B)/rho0 always starts from a negative one essentially independent of T, which was explained by the classical boundary scattering at the wall of the barrier in quasi-ballistic regime. The quantum Hall resistance of the electron-hole system has also been discussed.