THz response of GaAs/AlGaAs superlattices: from classical to quantum dynamics

Autor: K. D. Maranowski, Arthur C. Gossard, Uddalak Bhattacharya, S. J. Allen, B. J. Keay, Mark J. W. Rodwell, S. Zeuner
Rok vydání: 1997
Předmět:
Zdroj: Superlattices and Microstructures. 22:149-154
ISSN: 0749-6036
DOI: 10.1006/spmi.1996.0288
Popis: We have investigated the THz response of a series of GaAs/Al x Ga 1- x As superlattices with a variety of miniband widths. The samples range from the sequential resonant tunneling limit with a very narrow miniband to superlattices with a miniband width of 20 meV. The sequential tunneling superlattices show a transition from classical rectification at frequencies below 600 GHz to quantum response above 1 THz. In the quantum regime, the I– Vs show distinct peaks due to absorption and stimulated emission of up to seven THz-photons. At high a.c. field strengths (several kV cm -1 ) the photon-assisted channels dominate the transport, leading to dynamic localization, absolute negative conductance, and gain just below the Stark splitting of the quantum well ground-states. The transition from classical to quantum behavior takes place at a frequency where ħ ο∼Γ, where Γ≈2 meV is the ground-state level width in a single quantum well.
Databáze: OpenAIRE
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