阿秒
飞秒
半导体
电子
带隙
物理
激光器
极端紫外线
原子物理学
硅
半金属
光电子学
光学
超短脉冲
量子力学
作者
Martin Schultze,Krupa Ramasesha,C. D. Pemmaraju,Shunsuke A. Sato,Desiré Whitmore,Andrey Gandman,James S. Prell,Lauren J. Borja,David Prendergast,Kazuhiro Yabana,Daniel M. Neumark,Stephen R. Leone
出处
期刊:Science
[American Association for the Advancement of Science (AAAS)]
日期:2014-12-12
卷期号:346 (6215): 1348-1352
被引量:426
标识
DOI:10.1126/science.1260311
摘要
Electron transfer from valence to conduction band states in semiconductors is the basis of modern electronics. Here, attosecond extreme ultraviolet (XUV) spectroscopy is used to resolve this process in silicon in real time. Electrons injected into the conduction band by few-cycle laser pulses alter the silicon XUV absorption spectrum in sharp steps synchronized with the laser electric field oscillations. The observed ~450-attosecond step rise time provides an upper limit for the carrier-induced band-gap reduction and the electron-electron scattering time in the conduction band. This electronic response is separated from the subsequent band-gap modifications due to lattice motion, which occurs on a time scale of 60 ± 10 femtoseconds, characteristic of the fastest optical phonon. Quantum dynamical simulations interpret the carrier injection step as light-field–induced electron tunneling.
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