The ability to transfer electrons from valence to conduction band states in a semiconductor is the basis of modern electronics. Here, attosecond spectroscopy is used to resolve this process in real-time. The excitation of electrons across the band-gap of silicon by few-cycle laser pulses is found to induce lasting modifications of the XUV absorbance spectrum in steps synchronized with the laser electric field oscillations, indicative of light-field induced electron tunneling . In contrast, in SiO 2, a dielectric with 9 eV band-gap, similar excitation pulses are found to cause a transient field-induced polarizability without lasting population transfer .
- Advanced Materials Science
, Ramasesha, K., Bothschafter, E., Sommer, A., Pemmaraju, C. D., Sato, S. A., ... Leone, S. R. (2015). Attosecond Spectroscopy of Band-gap Dynamics
. Conference on Lasers and Electro-Optics
, FTh4C. 1. https://doi.org/10.1364/CLEO_QELS.2015.FTh4C.1