InAs/Al0.2Ga0.8Sb quantum well Hall effect sensors

Hall sensors with high sensitivity and excellent temperature stability were fabricated from quantum wells based on an InAs/Al 0.2 Ga 0.8 Sb heterostructure. The layers were grown on semi-insulating GaAs substrates by molecular beam epitaxy (MBE). Maximum Hall mobilities of 29.500 cm 2 V -1 s -1 with sheet electron concentrations of 2 × 10 12 cm -2 were measured at room temperature for an undoped quantum well structure. For a cross-shaped sensor, these excellent transport properties resulted in sensitivities of 0.9 T -1 (for voltage drive) and 300 V A -1 T -1 (for current drive). Additional doping of the InAs quantum well leads to an improvement of the temperature stability of the input resistance and sensitivity in the temperature range of - 100°C to + 150°C.