English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We employ ultra-broadband terahertz-midinfrared probe pulses to characterizethe optical response of photoinduced charge-carrier plasmas in high-resistivitysilicon in a reflection geometry, over a wide range of excitation densities(10^{15}-10^{19} cm^{-3}) at room temperature. In contrast to conventionalterahertz spectroscopy studies, this enables one to directly cover thefrequency range encompassing the resultant plasma frequencies. The intensityreflection spectra of the thermalized plasma, measured using sum-frequency(up-conversion) detection of the probe pulses, can be modeled well by astandard Drude model with a density-dependent momentum scattering time ofapprox. 200 fs at low densities, reaching approx. 20 fs for densities ofapprox. 10^{19} cm^{-3}, where the increase of the scattering rate saturates.This behavior can be reproduced well with theoretical results based on thegeneralized Drude approach for the electron-hole scattering rate, where thesaturation occurs due to phase-space restrictions as the plasma becomesdegenerate. We also study the initial sub-picosecond temporal development ofthe Drude response, and discuss the observed rise in the scattering time interms of initial charge-carrier relaxation, as well as the optical response ofthe photoexcited sample as predicted by finite-difference time-domainsimulations.

physical review. b, condensed matter and materials physics

Ultrafast dynamic conductivity and scattering rate saturation of  photoexcited charge carriers in silicon investigated with a midinfrared  continuum probe