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Coupling effects observed in the intersubband photocurrent of photovoltaic double-barrier quantum-well infrared detector

Intersubband-Kupplungseffekte im Photostromspektrum photovoltaischer Doppelbarrieren-Quantum Well-Infrarotdetektoren
: Ehret, S.; Schneider, H.


Journal of applied physics 79 (1996), No.12, pp.9369-9374
ISSN: 0021-8979
ISSN: 1089-7550
Journal Article
Fraunhofer IAF ()
MQW; photovoltaic; Photovoltaik; quantum well infrared photodetector; Quantum-Well-Infrarotphotodetektor; QWIP; resonant tunneling; resonantes Tunneln

The intersubband photocurrent in photovoltaic n-type GaAs/AlAs/Al(0.3)Ga(0.7)As double-barrier quantum-well infrared detectors is studied as a function of the applied external voltage and the incident wavelength. The photoresponse shows a significant photovoltaic behavior, resulting from a dopant segregation process during the growth. For an externally applied bias voltage, which compensates the built-in field, we find a multiple sign change of the photocurrent for varying incident wavelengths. A simulation of the wave functions indicates that this multiple sign change can he attributed to the coupling between the second subband in the GaAs quantum well and the subbands which are localized in the Al(0.3)Ga(0.7)As region.