EFFECT OF INTERSUBBAND COULOMB INTERACTION ON HOT-ELECTRON TRANSPORT IN 2-DIMENSIONAL AND ONE-DIMENSIONAL ELECTRON-SYSTEMS

We study the hot-electron transport properties of model GaAs-based qua si-two-dimensional (quantum-well) and quasi-one-dimensional (quantum w ire) systems having two occupied subbands by using the Lei-Ting balanc e-equations for two types of carriers. Both the intersubband electron- phonon interaction and intersubband Coulomb interaction are taken into account. Our numerical results show that when the electron density is high enough, the intersubband Coulomb interaction is substantially st rong in thermalizing the electrons between the different subbands. As a consequence, the one-type-of-carriers model (OTCM) is a good approxi mation for electron transport. However, in the cases of the lower elec tron densities, the intersubband Coulomb interaction is not strong eno ugh to fire the electrons in different subbands to share a common elec tron temperature and a more accurate two-types-of-carriers model (TTCM ) must be used for analysis.