Relaxation of an electron with energy E(k) by the emission of a phonon–plasmon. In the example, the mode (red solid arrow) is allowed, whereas (blue dashed) is forbidden.
Lower (red solid) and higher (blue dashed) plasma modes and with the upper allowed frequency transition imposed by energy conservation (dashed–dotted line). The allowed and forbidden regions for each transitions are marked in the graph, where it is also indicated the N value above which Fermi energy enters in conduction band (CB), The values of carrier density and discussed in the text are indicated as well with vertical black lines.
(a) Relaxation times (solid and dashed-dotted lines) and (dashed and dotted lines) for an electron in a confined state of a 8 nm wide quantum well, with a kinetic energy respectively of (b) Detail of the case for showing the exchange of the two modes.
Capture scattering scheme from a parabolic Ek bulk barrier state (dashed) to a quantum well state (solid) with a binding energy (a) No capture is possible via phonon-plasmon emission with frequency whereas capture via the mode is allowed with the emission of a phonon-plasmon of momentum q. (b) In this case the capture is possible through both plasmon modes.
Total capture time versus quantum well binding energy, for several values of 2D carrier density N (in the legend, values are in cm−2).
(a) Total capture time versus 2D carrier density, for several values of quantum well state binding energy (30, 50, 100, and 250 meV). (b) Capture times and versus carrier density (respectively via and ) for The vertical black lines correspond to density values as in Fig. 5 .
Total capture time versus 2D carrier density, for where the anti-screening effect is better visible.
Quantities definition list.
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