Long-wavelength infrared InAs/InGaSb type-II superlattice photovoltaic detectors

The design and characteristics of very long wavelength InAs/InGaSb strained layer superlattice photodiodes are presented. These photodiodes have cutoff wavelengths ranging from 12 to longer than 15 microns, and are among the longest wavelengths reported for photovoltaic detectors made using this material system. Structural, optical and electrical properties are reported. Measured quantum efficiencies are as high as 10% at 10 micron for a 0.7 micron thick structure at 77K. The absorption coefficients are excellent, however, the electrical properties still need improvement.