Quantum well infrared photodetectors hardiness to the nonideality of the energy band profile

We report results on the effect of a nonsharp and disordered potential in quantum well infrared photodetectors (QWIP). Scanning electronic transmission microscopy is used to measure the alloy profile of the structure which is shown to present a gradient of composition along the growth axis. Those measurements are used as inputs to quantify the effect on the detector performance (peak wavelength, spectral broadening, and dark current). The influence of the random positioning of the doping is also studied. Finally we demonstrate that QWIP properties are quite robust with regard to the nonideality of the energy band profile.