Ultrafast electron transport in layered semiconductors studied with femtosecond-laser photoemission
نویسندگان
چکیده
Femtosecond-laser photoemission was used to investigate the electron dynamics in the layered semiconductors MoSe2 and WSe2. Photoexcitation with 200-fs pulses of 2.03 eV light creates an electron gas with significant excess energy. Our measurements reveal a strong transient enhancement in the diffusive transport of the most energetic electrons relative to the conduction-band minimum. Additionally, we demonstrate that the surfaces of these layered chalcogenides are electronically passivated and we give an upper bound for the density of defect states within the band gap. @S0163-1829~97!02443-0#
منابع مشابه
Ultrafast Microscopy: Imaging Light with Photoelectrons on the Nano-Femto Scale.
Experimental methods for ultrafast microscopy are advancing rapidly. Promising methods combine ultrafast laser excitation with electron-based imaging or rely on super-resolution optical techniques to enable probing of matter on the nano-femto scale. Among several actively developed methods, ultrafast time-resolved photoemission electron microscopy provides several advantages, among which the fo...
متن کاملBroadband ultrafast nonlinear absorption and nonlinear refraction of layered molybdenum dichalcogenide semiconductors.
A series of layered molybdenum dichalcogenides, i.e., MoX₂ (X = S, Se and Te), were prepared in cyclohexyl pyrrolidinone by a liquid-phase exfoliation technique. The high quality of the two-dimensional nanostructures was verified by transmission electron microscopy and absorption spectroscopy. Open- and closed-aperture Z-scans were employed to study the nonlinear absorption and nonlinear refrac...
متن کاملSpin-flip processes and ultrafast magnetization dynamics in Co: Unifying the microscopic and macroscopic view of femtosecond magnetism.
The femtosecond magnetization dynamics of a thin cobalt film excited with ultrashort laser pulses has been studied using two complementary pump-probe techniques, namely, spin-, energy-, and time-resolved photoemission and the time-resolved magneto-optical Kerr effect. Combining the two methods, it is possible to identify the microscopic electron spin-flip mechanisms responsible for the ultrafas...
متن کاملUltrafast Mid-Infrared Dynamics in Quantum Cascade Lasers
This report summarizes the entire research period. In this program, we performed experiments using a femtosecond mid-infrared pump-probe system implemented for QCL samples operating at 4.6 and 5.3 μm. We employed femtosecond time-resolved pump-probe measurements to probe the nature of the transport through the laser structure via the dynamics of the gain. The gain recovery was determined by the...
متن کاملSuperdiffusive Spin Transport and Ultrafast Magnetization Dynamics Femtosecond spin transport as the route to ultrafast spintronics
Battiato, M. 2013. Superdiffusive Spin Transport and Ultrafast Magnetization Dynamics: Femtosecond spin transport as the route to ultrafast spintronics. Acta Universitatis Upsaliensis. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1061. 62 pp. Uppsala. ISBN 978-91-554-8722-5. The debate over the origin of the ultrafast demagnetization has be...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1997