A very long wavelength broadband infrared detector, sensitive over a 10–16 μm spectral range, based on GaAs/AlxGa1−xAs
quantum wells grown by molecular beam epitaxy, has been demonstrated. Wavelength broadening of Δλ/λp ∼ 42%
is observed to be about a 400% increase compared to a typical bound-to-quasibound quantum well infrared photodetector (QWIP). In this device structure, which is different from typical QWIP device structures, two different gain mechanisms associated with photocurrent electrons and dark current electrons were observed and explained. Even with broader response, D∗ ∼ 1×1010 cm/W
at T = 55 K
is comparable to regular QWIPs with similar cutoff wavelengths. © 1998 American Institute of Physics.