Nanoscale engineering of photoelectron processes for infrared detection
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In this dissertation, we investigate the influence of different nanostructures on photoelectron processes in order to achieve infrared detection. In the first part, we make a review of the principal families of infrared detectors, following we study the effect of local potential barriers on quantum dot infrared detectors properties. To investigate this effect we fabricated several QD structures with different positions of dopants and various levels of doping (from 2.5 to 9 electrons per dot). The nature and the relative height of potential barriers as a function of doping and dopant positions have been determined using nextnano3 software, and we propose a model to explain the exponential increase of photoresponse with the increase of barrier height. Thereafter, different approaches in order to increase responsivity of our samples and/or decrease their dark current were studied. Finally, a voltage tunable long-wavelength infrared dual color photodetector made from an asymmetrical doped couple double quantum well infrared photodetector, was studied, and notably the possibility of using it as a multi-color photodetector.