ELECTRON INTERSUBBAND SCATTERING IN REAL QUANTUM WIRES

The rates of electron intra- and intersubband scattering by surface optical (SO) and confined longitudinal optical (LO) phonons in quasi-one-dimensional GaAs/AlAs quantum wires (QWIs) are calculated. It is shown that electron-SO-phonon intersubband scattering can be resonant, so that the scattering rate tends to infinity when intersubband energy separation approaches SO phonon energy. The energy dependence of the total scattering rate in ideal QWIs exhibits multiple sharp peaks related to intersubband transitions. The scattering rates in the real QWIs with variable thickness are calculated. The results show that even small variation in thickness leads to the significant broadening of the very first peaks and complete washing-out of the peak-like structure at higher energies. Monte Carlo simulations of electron transport in the QWI have been performed. It is demonstrated that electron drift velocity in the QWI is considerably suppressed by electron intersubband scattering and is considerably lower than the bulk material values. The role of SO phonons in electron energy dissipation is discussed. © 1992.