Performance of corrugated quantum well infrared photodetectors

Corrugated quantum well infrared photodetectors (C-QWIPs) use total internal reflection to couple normal incident light into the detectors. In this work, we report the performance of C-QWIPs at different wavelengths. Compared with 45 degrees edge coupling, a C-QWIP increases the background photocurrent to dark current ratio r(1) by a factor between 2.4 and 4.4, thereby increasing the background-limited temperature by 3 to 5 K. The detectivity D* is increased by a factor of 2.4. We applied the C-QWIP to two-color detection and obtained precision thermometric measurements. We have also fabricated and characterized a 256 x 256 C-QWIP array with cutoff wavelength at 11.2 mu m. The uncorrected nonuniformity (sigma/mean) in the central 128 x 128 subarray is 2.3%. The NE Delta T at 63 K is estimated to be 23 mK. Furthermore, we have shown that r(1) can be further increased by fabrication of the C-QWIP into the corrugated hot-electron transistor structure. The enhanced performance of the corrugated structure, combined with its simple processing steps, greatly improves the QWIP technology.