Far-infrared intersubband photodetectors based on double-step III-nitride quantum wells

Far-infrared photoconductive detectors based on intersubband transitions in III-nitride semiconductor quantum wells are demonstrated. The device active material is based on a double-step quantum-well design, where two different (Al)GaN compositions are used both in the wells and in the barriers. With this approach, one can create a virtually flat multiple-quantum-well potential energy profile, where the deleterious effects of the intrinsic spontaneous and piezoelectric fields of nitride heterostructures are almost completely eliminated. Photocurrent spectra centered at a wavelength of 23 mu m (13 THz frequency) are resolved up to 50 K, with responsivity of approximately 7 mA/W. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729470]