Redshifting of a bound-to-continuum GaAs/AlGaAs quantum-well infrared photodetector response via laser annealing

The effect of laser annealing on important detector characteristics such as dark current, spectral response, and absolute responsivity is investigated for bound-to-continuum GaAs/AlGaAs quantum-well infrared photodetectors (QWIPs) operating in the 8–12 μm wavelength regime. A set of experiments was conducted on QWIPs fabricated from both as-grown and laser-annealed multiple-quantum-well structures. Compared to the as-grown structure, the peak spectral response of the laser-annealed structure was shifted to longer wavelengths, though absolute responsivity was decreased by about a factor of two. In addition, over a wide range of bias levels, the laser-annealed QWIPs exhibited a slightly lower dark current compared to the as-grown QWIPs. Thus, the postgrowth control of GaAs/AlGaAs quantum-well composition profiles by laser annealing offers unique opportunities to fine tune various aspects of a QWIP’s response.