Na. Bannov et al., ELECTRON MOMENTUM RELAXATION-TIME AND MOBILITY IN A FREESTANDING QUANTUM-WELL, Journal of applied physics, 78(9), 1995, pp. 5503-5510
Kinetic characteristics of the electron transport in a free-standing q
uantum well are studied theoretically. The quantization of acoustic ph
onons in a free-standing quantum well is taken into account and electr
on interactions with confined acoustic phonons through the deformation
potential are treated rigorously. The kinetic equation for the electr
on distribution function is solved numerically for nondegenerate as we
ll as degenerate electron gases and the electron momentum relaxation t
ime and the electron mobility are obtained. At high lattice temperatur
es the electron momentum relaxation time is very similar to that obtai
ned in the test particle approximation. Its dependence on the electron
energy has steps which occur at the threshold energies for the dilata
tional phonons because an additional electron scattering by the corres
ponding acoustic phonon becomes important. The first mode makes the ma
in contribution to the electron scattering, the contributions of the z
eroth and the second modes are also important, the third and the highe
r modes practically unnoticeable for the studied electron concentratio
ns and quantum well width. At lattice temperatures lower than the ener
gy of the first dilatational acoustic mode the electron momentum relax
ation time dependence on energy has additional peaks (in comparison wi
th the test particle approximation) associated with electron scatterin
g by several lowest acoustic phonon modes. These peaks occur near the
Fermi energy in the degenerate case and in the energy range of the fir
st dilatational modes in the nondegenerate case. They are especially p
ronounced for the degenerate electron gas. The temperature dependence
of the electron mobility is similar to that described by the Bloch-Gru
neisen formula, however we obtained a smaller negative exponent in the
low temperature region. (C) 1995 American Institute of Physics.