GaN/AlN-based quantum-well infrared photodetector for 1.55 <i>µ</i>m

We report optical absorption and photocurrent measurements on a GaN/AlN-based superlattice. The optical absorption has a full width at half maximum of 120 meV and takes place at an energy of 660 meV (5270 cm^–1); this corresponds to a wavelength of 1.9 <i>µ</i>m. While the optical absorption remained unchanged up to room temperature, the photocurrent signal could be observed up to 170 K. With respect to the optical absorption, the photocurrent peak was slightly blueshifted (710 meV/5670 cm^–1) and had a narrower width of 115 meV. Using this quantum-well infrared photodetector, we were able to measure the spectrum of a 1.55 <i>µ</i>m superluminescent light-emitting diode.