Options
1999
Conference Paper
Titel
Suppressing recombination noise in quantum well infrared photodetectors
Alternative
Unterdrückung des Rekombinationsrauschens in Quantumwell Infrarot Detektoren
Abstract
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.
Author(s)