Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Suppressing recombination noise in quantum well infrared photodetectors

Unterdrückung des Rekombinationsrauschens in Quantumwell Infrarot Detektoren
: Schönbein, C.; Schneider, H.; Rehm, R.; Walther, M.

Li, S.S. ; Electrochemical Society -ECS-, Dielectric Science and Technology Division; Electrochemical Society -ECS-, Electronics Division; Electrochemical Society -ECS-, Luminescent and Display Materials Division:
Long wavelength infrared detectors and arrays. Physics and applications. Proceedings of the Sixth International Symposium on Long Wavelength Infrared Detectors and Arrays
Pennington,NJ: ECS, 1999 (Electrochemical Society. Proceedings 98-21)
ISBN: 1-566-77215-X
S.158-169 : Ill., Lit.
International Symposium on Long Wavelength Infrared Detectors and Arrays <6, 1998, Boston/Mass.>
Fraunhofer IAF ()
GaAs/AlGaAs; noise; quantum well infrared photodetector; QWIP; Rauschen

We present noise current measurements on a specific elms of quanturn well infrared photodetectors (QWIPs). The design of the detectors implies a carrier mean free path of exactly one period of the superlattices with N = 20 periods. This leads to a deterministic carrier capture process, resulting in the lack of recombination noise. The noise current in this type of detector is given by I(noise)=(root of4e/gn- 1/(2N))I(dark)delta f) with the electron charge e, the noise gain gn, =1/(Npc) (where pc is the carrier capture probability), the dark current I(dark) and the measurement bandwidth delta f. For pc = 1 this expression reduces to the shot noise expression for N series-connected photo junctions. From the design of the structures we expect a noise gain of gn = 1/N = 0.05 at sufficiently small bias voltages, which is confirmed by the measurements in combination with the appropriate noise model. With this new detector, we achieve detectivities comparable to the detectivities of conventio nal QWIPs at ten times smaller currents.