Effect of simultaneous electric and magnetic fields on a GaAs/AlGaAs superlattice miniband probed by intersubband electron transitions

Vertical transport has been measured on GaAs/AlGaAs quantum-well superlattice infrared photodetectors in crossed electric and magnetic fields. The carriers, promoted by either thermal or photoexcitation from the doped ground state of the quantum well, move through the miniband formed in the superlattice as a result of the applied voltage. Measurements of electrical conductivity and photocurrent have been made in electric fields up to 30 kV/cm and magnetic fields up to 7.5 T on structures with differing miniband widths. Mobilities, scattering times, and drift velocities have been deduced in the Framework of a conventional model of miniband transport, in which Landau quantization has been neglected, The behavior of the system is discussed in terms of competition between electric and magnetic field breakup of the miniband into individual states.