Corrugated quantum well infrared photodetectors (C-QWIPs) utilize total internal reflection to couple normal incident light into the detectors. In this work, we performed a systematic study on C-QWIPs with cutoff wavelength λc
ranging from 5 to 17.3 μm and device areas ranging from 50×50 μm2
to 500×500 μm2.
We found that the coupling efficiency of the C-QWIPs is, indeed, independent of both the detection wavelength and the pixel size, as expected. Compared to devices with a standard 45° edge coupling, the C-QWIP increases the background photocurrent to a dark current ratio by a factor between 2.4 and 4.4, thereby increasing the background limited temperature by 3–5 K. At the same time, the detectivity D∗
is also increased by a factor around 2.4. For λc = 9.4 μm,
the peak detectivity Dp∗
and the blackbody detectivity Dbb∗
at 78 K are measured to be 4.5×1010 cm /W
and 4.5×109 cm/W,
respectively. © 1997 American Institute of Physics.