Observation of a phonon bottleneck effect on the thermal depopulation from a photoexcited shallow defect in silicon

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Autori principali: Revuelta, Sergio, Wang, Hai I., Bonn, Mischa, Canovas, Enrique
Natura: Preprint
Pubblicazione: 2025
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author Revuelta, Sergio
Wang, Hai I.
Bonn, Mischa
Canovas, Enrique
author_facet Revuelta, Sergio
Wang, Hai I.
Bonn, Mischa
Canovas, Enrique
contents We report the observation of a phonon bottleneck effect impacting the thermal depopulation of photoexcited shallow defects in high-resistivity silicon. Using time-resolved terahertz (THz) spectroscopy, near-band-gap excitation produces a pronounced temporal delay in photoconductivity, indicating that a fraction of photogenerated charge carriers is temporarily trapped immediately after excitation. By analyzing the frequency-resolved complex photoconductivity as a function of pump-probe delay and photon energy, we attribute this delay to the presence of a localized shallow state situated approximately 40 meV from the band edge, which competes with silicon's indirect band-to-band absorption. The zero-order kinetic profile of the temporal delay, its invariance with respect to photon flux, and its temperature dependence collectively support the existence of a phonon bottleneck that hinders the thermal release of electrons from this shallow trap. this represents experimental evidence of a phonon bottleneck effect associated with the thermal activation of shallow traps in photoexcited silicon. These findings provide microscopic insight into carrier relaxation dynamics in silicon and highlight the significance of electron-phonon interactions in the ultrafast processes governing materials used in optoelectronic applications.
format Preprint
id arxiv_https___arxiv_org_abs_2511_19092
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Observation of a phonon bottleneck effect on the thermal depopulation from a photoexcited shallow defect in silicon
Revuelta, Sergio
Wang, Hai I.
Bonn, Mischa
Canovas, Enrique
Materials Science
Mesoscale and Nanoscale Physics
Other Condensed Matter
We report the observation of a phonon bottleneck effect impacting the thermal depopulation of photoexcited shallow defects in high-resistivity silicon. Using time-resolved terahertz (THz) spectroscopy, near-band-gap excitation produces a pronounced temporal delay in photoconductivity, indicating that a fraction of photogenerated charge carriers is temporarily trapped immediately after excitation. By analyzing the frequency-resolved complex photoconductivity as a function of pump-probe delay and photon energy, we attribute this delay to the presence of a localized shallow state situated approximately 40 meV from the band edge, which competes with silicon's indirect band-to-band absorption. The zero-order kinetic profile of the temporal delay, its invariance with respect to photon flux, and its temperature dependence collectively support the existence of a phonon bottleneck that hinders the thermal release of electrons from this shallow trap. this represents experimental evidence of a phonon bottleneck effect associated with the thermal activation of shallow traps in photoexcited silicon. These findings provide microscopic insight into carrier relaxation dynamics in silicon and highlight the significance of electron-phonon interactions in the ultrafast processes governing materials used in optoelectronic applications.
title Observation of a phonon bottleneck effect on the thermal depopulation from a photoexcited shallow defect in silicon
topic Materials Science
Mesoscale and Nanoscale Physics
Other Condensed Matter
url https://arxiv.org/abs/2511.19092