InAs/Al0.2Ga0.8Sb quantum well Hall sensors with improved temperature stability

Cross-shaped Hall sensors with high sensitivity and excellent temperature s tability were fabricated from quantum wells based on an InAs/Al0.2Ga0.8Sb h eterostructure. The layers were grown on semi-insulating GaAs substrates by molecular beam epitaxy. Maximum Hall mobilities of 215 000 cm(2)/V s with sheet carrier concentrations of 9 x 10(11) cm(-2) were measured at 4.2 K fo r an undoped quantum well structure. These transport properties result in s ensitivities as high as 3 T-1 (for voltage drive) and 650 Omega/T (for curr ent drive). Additional Si delta doping in the middle of the InAs quantum we ll leads to a highly improved temperature stability of the sensitivities. ( C) 1999 American Institute of Physics. [S0034-6748(99)03306-7].