Magneto-transport measurements of two-dimensional electron systems in GaAs and InSb Mentors Chris Palmstrom, Sean Harrington, and Mihir Pendharkar (ECE / MRL)
Taozhi Guo

Confinement of electrons in a thin layer of narrow band-gap GaAs surrounded by layers of larger band-gap AlGaAs leads to quantization of allowed energy levels in GaAs. When only the lowest energy state is occupied, electron transport in GaAs is purely two-dimensional (referred to as 2D electron gas or 2DEG). Upon cooling down a 2DEG to cryogenic temperatures, quantum mechanical phenomenon like the Integer Quantum Hall Effect can be observed. This work focuses on room temperature and low temperature Hall measurements of GaAs/AlGaAs and InSb/AlInSb 2DEGs grown by Molecular Beam Epitaxy. With the aim of developing a quick feedback for MBE grown 2DEGs, sheet carrier density and mobility measured at room temperature has been correlated to dopants incorporated during MBE growth. At 300K, GaAs QWs showed a peak mobility of 6100 cm2/Vs while InSb QWs showed a peak mobility of 11000 cm2/Vs. High mobility samples were further measured at 2 Kelvin and Integer Quantum Hall Effect was observed.

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