naa a22 4500 510816517 CHVBK 20180411083510.0 cr unu---uuuuu 180411e20131201xx s 000 0 eng 10.1007/s11468-013-9582-2 doi (NATIONALLICENCE)springer-10.1007/s11468-013-9582-2 Effects of Carrier Confinement and Intervalley Scattering on Photoexcited Electron Plasma in Silicon [Elektronische Daten] [A. Sieradzki, Z. Kuznicki] The ultrafast reflectivity of silicon, excited and probed with femtosecond laser pulses, is studied for different wavelengths and energy densities. The confinement of carriers in a thin surface layer delimited by a nanoscale Si-layered system buried in a Si heavily-doped wafer reduces the critical density of carriers necessary to create the electron plasma by a factor of ten. We performed two types of reflectivity measurements, using either a single beam or two beams. The plasma strongly depends on the photon energy density because of the intervalley scattering of the electrons revealed by two different mechanisms assisted by the electron-phonon interaction. One mechanism leads to a negative differential reflectivity that can be attributed to an induced absorption in X valleys. The other mechanism occurs, when the carrier population is thermalizing and gives rise to a positive differential reflectivity corresponding to Pauli-blocked intervalley gamma to X scattering. These results are important for improving the efficiency of Si light-to-electricity converters, in which there is a possibility of multiplying carriers by nanostructurization of Si. The Author(s), 2013 Ultrafast processes nationallicence Electron-hole plasma nationallicence Nanostructured silicon nationallicence Sieradzki A. Institute of Physics, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland aut Kuznicki Z. Photonic Systems Laboratory, Pôle API Parc d'Innovation, Boulevard Sébastien Brant, BP 10413, 67400, Illkirch, France aut Plasmonics Springer US; http://www.springer-ny.com 8/4(2013-12-01), 1643-1646 1557-1955 8:4<1643 2013 8 11468 https://doi.org/10.1007/s11468-013-9582-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11468-013-9582-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sieradzki A. Institute of Physics, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland aut NATIONALLICENCE 700 1- Kuznicki Z. Photonic Systems Laboratory, Pôle API Parc d'Innovation, Boulevard Sébastien Brant, BP 10413, 67400, Illkirch, France aut NATIONALLICENCE 773 0- Plasmonics Springer US; http://www.springer-ny.com 8/4(2013-12-01), 1643-1646 1557-1955 8:4<1643 2013 8 11468 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer