Applications of Ultrafast TeraHertz Pulses for Intra-Excitonic Spectroscopy of Quasi-2D Electron–Hole Gases
| Autor: | M.A. Carnahan, Robert A. Kaindl, Daniel S. Chemla, Daniel Hägele |
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| Rok vydání: | 2007 |
| Předmět: |
Physics
Terahertz radiation business.industry Exciton Physics::Optics Electron hole Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Electronic Optical and Magnetic Materials Terahertz spectroscopy and technology Photoexcitation Condensed Matter::Materials Science Excited state Optoelectronics Electrical and Electronic Engineering Atomic physics Spectroscopy business Quantum well |
| Zdroj: | Journal of Nanoelectronics and Optoelectronics. 2:83-89 |
| ISSN: | 1555-1318 1555-130X |
| Popis: | Excitons are of fundamental interest and of importance foropto-electronic applications of bulk and nano-structured semiconductors.This paper discusses the utilization of ultrafast terahertz (THz) pulsesfor the study of characteristic low-energy excitations of photoexcitedquasi 2D electron-hole (e-h) gases. Optical-pump THz-probe spectroscopyat 250-kHz repetition rate is employed to detect characteristic THzsignatures of excitons and unbound e-h pairs in GaAs quantum wells.Exciton and free-carrier densities are extracted from the data using atwo-component model. We report the detailed THz response and pairdensities for different photoexcitation energies resonant to heavy-holeexcitons, light-hole excitons, or the continuum of unbound pairs. Suchexperiments can provide quantitative insights into wavelength, time, andtemperature dependence of the low-energy response and composition ofoptically excited e-h gases in low-dimensionalsemiconductors. |
| Databáze: | OpenAIRE |
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