Vn. Stavrou et al., Electron scattering and capture rates in quantum wells by emission of hybrid optical phonons - art. no. 205304, PHYS REV B, 6320(20), 2001, pp. 5304
Intra- and intersubband scattering and electron capture rates are considere
d when mediated by hybrid optical phonons in an AlAs/GaAs/AlAs double heter
ostructure confined between two outer metallic barriers. In evaluating scat
tering rates we concentrate first on an infinite quantum well for the elect
rons and show that the presence of the outer metal barriers results in redu
ctions of the intra- and intersubband scattering rates due to the suppressi
on of the interfacelike modes. For a quantum well with a finite depth we fi
nd that the outer barriers are responsible for the existence of a discrete
energy spectrum above the well. The electron capture process under these ci
rcumstances is defined as the electron transition from the first electron s
ubband above the well to all possible subbands inside the well by the emiss
ion of hybrid phonons. Explicit calculations reveal that the capture rates
are characterized by sharp peaks, referred to as electron resonances, which
arise when a new electron state is generated on increasing the quantum wel
l width. Other sharp peaks are identified as phonon resonances and arise wh
en the energy of the initial state differs by a phonon energy from an elect
ron state at the bottom of a quantum well subband.