Antimony-based type-II superlattice infrared photodetectors on indium-arsenide substrates

摘要

The wide variety of applications for mid- and far-infrared detection hasspurred the study of cutting-edge technologies for use in the next genera-tion of detectors in place of the current systems, such as mercury cadmiumtelluride. While type-II superlattices over a number of advantages in designand material quality, theoretical predictions of their high performance haveyet to be realized. This work concentrates on novel designs, fabrication, andcharacterization of type-II superlattice infrared detectors.In this work we present the first InAs/GaSb type-II superlattice photode-tectors grown on an InAs substrate via metal-organic chemical vapor depo-sition. The design and fabrication of the devices are detailed, along withseveral characterization processes, including low-temperature electron beaminduced current (EBIC) to study structural defects. Through this work, theoptical absorption of the undoped substrate was shown to be significantlylower than that of GaSb. The detectors have a cutoff wavelength (50% re-sponsivity) of 9.5 um at 78 K. Their R0A values are on the order of 10^-2Ohm*cm2. The typical peak responsivity is 1.9 A/W, and the devices have apeak detectivity of 6.8 * 10^9 cm*Hz^1/2 /W at 78 K.