ELECTRIC-FIELD EFFECTS IN ALGAAS-GAAS SYMMETRICAL AND ASYMMETRIC COUPLED QUANTUM-WELLS

A theoretical study of energy level shift and field-induced tunneling in symmetric and asymmetric coupled quantum wells is presented. Energy level shift is calculated from the time-independent Schrodinger equation using the inverse power method. The time evolution of an electron wavepackage is shown by the application of the time-development operator of the time-independent Schrodinger equation. Energy level shift in coupled quantum wells is found to be enhanced in comparison to single quantum wells. In addition, the energy level shift in coupled quantum wells is found to be nearly linear with applied field (in contrast to the parabolic relationship found in the single quantum wells). Oscillation frequencies for electrons in symmetric and asymmetric coupled quantum wells are evaluated versus applied field and compared to semiclassical predictions. In addition, tunneling lifetimes in symmetric and asymmetric coupled quantum wells are evaluated versus applied field.