Scattering of electrons by confined interface polar optical phonons in a double-barrier heterostructure

Abstract

It is shown that capture of the surface (interface) phonons can occur in a double-barrier heterostructure in addition to the capture of bulk polar optical phonons. The strength of interaction of electrons with confined interface phonons becomes lower as the thickness of the phonon well (a semiconductor layer where phonons are captured) is decreased. A new approach is suggested for reducing the scattering of electrons by polar optical phonons in a double-barrier quantum well; this approach is based on separate capture of phonons in narrow phonon wells. The calculated scattering rate with the capture of interface phonons into the GaAs/InAs/GaAs and AlAs/GaAs/AlAs quantum wells taken into account is found to be much lower than the rate obtained in the approximation of scattering of electrons by bulk phonons. A multifold decrease in the rate of electron-phonon scattering in the AlAs/GaAs/AlAs quantum well is obtained by separating this well by the monomolecular InAs layer that is transparent for electrons but acts as a reflecting barrier for polar optical phonons.