THEORETICAL AND EXPERIMENTAL INVESTIGATION OF THE DRIFT VELOCITY IN ALGAAS/GAAS HETEROSTRUCTURES

The drift velocity of hot electrons in AlGaAs/GaAs heterostructures is measured at different temperatures by a pulsed I-V technique up to electric fields of 1.2 kV/cm. The experimental results are compared with theoretical drift velocities deduced from the Boltzmann integral equation and a balance equation method. The calculations are carried out with selfconsistent and Stern-Howard wave functions taking into account polar optical phonon and ionized impurity scattering as well as electron-electron collisions. At low field strengths both theoretical methods lead to drift velocities which are in good agreement with the experimental data. It is shown that for higher lattice temperatures and higher electric field strengths intersubband scattering has to be taken into account in the theoretical models.