Stronger femtosecond excitation causes slower electron-phonon coupling in silicon
Electron-hole pairs in semiconductors are essential for solar cells and fast electronic circuitry, but the competition between carrier transport and relaxation into heat limits the efficiency and speed. Here we use ultrafast electron diffraction with terahertz pulse compression to measure the electr...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2025-05-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.7.023114 |
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| _version_ | 1849324482109374464 |
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| author | A. B. Swain J. Kuttruff J. Vorberger P. Baum |
| author_facet | A. B. Swain J. Kuttruff J. Vorberger P. Baum |
| author_sort | A. B. Swain |
| collection | DOAJ |
| description | Electron-hole pairs in semiconductors are essential for solar cells and fast electronic circuitry, but the competition between carrier transport and relaxation into heat limits the efficiency and speed. Here we use ultrafast electron diffraction with terahertz pulse compression to measure the electron-phonon decay rate in single-crystal silicon as a function of laser excitation strength. We find that the excited electrons relax slower into phonons for higher carrier densities. The electron-phonon scattering rate changes in a nonlinear way from 400 fs at ∼2×10^{20}/cm^{3} to 1.2 ps at ∼4×10^{20}/cm^{3}. These results indicate that a hot electron gas quenches the scattering into phonons in a temperature-dependent way. Ultrafast electronic circuitry of silicon should therefore work faster and provide higher bandwidths at lower carrier densities. |
| format | Article |
| id | doaj-art-6a6494eebf0b42fb8b8872db8e98e535 |
| institution | Kabale University |
| issn | 2643-1564 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj-art-6a6494eebf0b42fb8b8872db8e98e5352025-08-20T03:48:42ZengAmerican Physical SocietyPhysical Review Research2643-15642025-05-017202311410.1103/PhysRevResearch.7.023114Stronger femtosecond excitation causes slower electron-phonon coupling in siliconA. B. SwainJ. KuttruffJ. VorbergerP. BaumElectron-hole pairs in semiconductors are essential for solar cells and fast electronic circuitry, but the competition between carrier transport and relaxation into heat limits the efficiency and speed. Here we use ultrafast electron diffraction with terahertz pulse compression to measure the electron-phonon decay rate in single-crystal silicon as a function of laser excitation strength. We find that the excited electrons relax slower into phonons for higher carrier densities. The electron-phonon scattering rate changes in a nonlinear way from 400 fs at ∼2×10^{20}/cm^{3} to 1.2 ps at ∼4×10^{20}/cm^{3}. These results indicate that a hot electron gas quenches the scattering into phonons in a temperature-dependent way. Ultrafast electronic circuitry of silicon should therefore work faster and provide higher bandwidths at lower carrier densities.http://doi.org/10.1103/PhysRevResearch.7.023114 |
| spellingShingle | A. B. Swain J. Kuttruff J. Vorberger P. Baum Stronger femtosecond excitation causes slower electron-phonon coupling in silicon Physical Review Research |
| title | Stronger femtosecond excitation causes slower electron-phonon coupling in silicon |
| title_full | Stronger femtosecond excitation causes slower electron-phonon coupling in silicon |
| title_fullStr | Stronger femtosecond excitation causes slower electron-phonon coupling in silicon |
| title_full_unstemmed | Stronger femtosecond excitation causes slower electron-phonon coupling in silicon |
| title_short | Stronger femtosecond excitation causes slower electron-phonon coupling in silicon |
| title_sort | stronger femtosecond excitation causes slower electron phonon coupling in silicon |
| url | http://doi.org/10.1103/PhysRevResearch.7.023114 |
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