Ballistic effects and intersubband excitations in multiple quantum well structures
| Autor: | Harald Schneider, Markus Walther, K. Schwarz, C. Schönbein |
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| Přispěvatelé: | Publica |
| Rok vydání: | 1998 |
| Předmět: |
Photocurrent
Physics infrared photodetector Condensed matter physics Mean free path intersubband excitation coherent transport kohärenter Transport Electron Infrarot-Photodetektor Condensed Matter Physics Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials Intersubband-Anregung Ballistic conduction Infrared detector intersubband transition Quantum well Excitation Coherence (physics) |
| Zdroj: | ResearcherID |
| ISSN: | 1386-9477 |
| DOI: | 10.1016/s1386-9477(98)00008-3 |
| Popis: | We have studied the transport properties of electrons in asymmetric quantum well structures upon far-infrared optical excitation of carriers from the lowest subband into the continuum. Here the photocurrent consists of a coherent component originating from ballistic transport upon excitation, and of an incoherent part associated with asymmetric diffusion and relaxation processes, which occur after the coherence has been lost. The signature of the coherent contribution is provided by a sign reversal of the photocurrent upon changing the excitation energy. This sign reversal arises from the energy-dependent interference between continuum states, which have a twofold degeneracy characterized by positive and negative momenta. The interference effect also allows us to estimate the coherent mean free path ( > 20 nm at 77 K). In specifically designed device structures, we use both the coherent and incoherent components in order to achieve a pronounced photovoltaic infrared response for detect or applications. |
| Databáze: | OpenAIRE |
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