V. Ryzhii et al., High-frequency characteristics of quantum well infrared photodetectors with blocking barrier, JPN J A P 1, 40(5A), 2001, pp. 3137-3142
We have developed an analytical model for quantum well infrared photodetect
ors (QWIPs) with a superlattice serving as the absorption region and a bloc
king barrier. The explicit analytical expression for the frequency-dependen
t responsivity is derived as a function of the QWIP structural parameters.
Using this expression we calculate the 3 dB cut-off frequency and bandwidth
-response efficiency. The bandwidth of QWIPs with a moderate number of QWs
can exceed 100 GHz exhibiting fairly large responsivity. We show that a fas
t tunneling filling of the absorption region by the electrons injected from
the emitter contact results in a significant modification of the high-freq
uency properties of the QWIP under consideration compared to the standard Q
WIPs, in particular, in the elimination of the low-frequency peak of the re
sponsivity.