Theory of Thermal Relaxation of Electrons in Semiconductors
| Autor: | Maria K. Y. Chan, Pierre Darancet, Sridhar Sadasivam |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Phonon
FOS: Physical sciences General Physics and Astronomy 02 engineering and technology Electron 01 natural sciences Condensed Matter::Materials Science symbols.namesake Condensed Matter::Superconductivity Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0103 physical sciences 010306 general physics Physics Condensed Matter - Materials Science Condensed Matter - Mesoscale and Nanoscale Physics Condensed matter physics business.industry Materials Science (cond-mat.mtrl-sci) Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 021001 nanoscience & nanotechnology Thermalisation Semiconductor Molecular vibration Boltzmann constant symbols Condensed Matter::Strongly Correlated Electrons Charge carrier 0210 nano-technology business Excitation |
| Zdroj: | Physical Review Letters. 119 |
| ISSN: | 1079-7114 0031-9007 |
| DOI: | 10.1103/physrevlett.119.136602 |
| Popis: | We compute the transient dynamics of phonons in contact with high energy "hot" charge carriers in 12 polar and non-polar semiconductors, using a first-principles Boltzmann transport framework. For most materials, we find that the decay in electronic temperature departs significantly from a single-exponential model at times ranging from 1 ps to 15 ps after electronic excitation, a phenomenon concomitant with the appearance of non-thermal vibrational modes. We demonstrate that these effects result from the slow thermalization within the phonon subsystem, caused by the large heterogeneity in the timescales of electron-phonon and phonon-phonon interactions in these materials. We propose a generalized 2-temperature model accounting for the phonon thermalization as a limiting step of electron-phonon thermalization, which captures the full thermal relaxation of hot electrons and holes in semiconductors. A direct consequence of our findings is that, for semiconductors, information about the spectral distribution of electron-phonon and phonon-phonon coupling can be extracted from the multi-exponential behavior of the electronic temperature. |
| Databáze: | OpenAIRE |
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