Hybrid Boltzmann transport-Schrodinger equation model for quantumwell injection transit (QWITT) diodes

摘要

The authors report a self-consistent study of steady-statenonstationary transport in QWITT diodes using the pure state tunnelingtheory to treat transport through the double barrier quantum well regionand the Boltzmann transport equation (BTE) to treat transport in therest of the device. The distribution functions at the boundaries of thedouble barrier structure are evaluated, taking into account bothtunneling and phonon scattering processes. It si found that velocityovershoot occurs in a region of 50 nm within the double barrier region,with a peak velocity of about 8×107 cm/sec occurringimmediately after injection. The velocity falls rapidly to 7-8×106 cm/sec over a distance of 50 nm. Due to the high energy ofcarriers injected from the quantum well and the presence of highelectric fields, the extent of the velocity overshoot in the driftregion of QWITT diodes is limited