Investigation of InAsSbP quantum dot mid-infrared sensors

Abstract. This work presents the results of investigations of a low bias mid-infrared(IR) photoconductive cell (PCC) with InAsSbP quantum dots (QDs). The self-assembled nanostructures were grown on an InAs(100) substrate by modified liquid phase epitaxy. The coarsening of the QDs due to Ostwald ripening was discussed. Hysteresis with a remnant capacitance of 0.483 pF and contra-directional oscillations on the PCC's capacitance–voltage characteristic at 78 K were observed. Additionally, peaks at 3.48, 3.68 and 3.89 μm on the room temperature photoresponse spectrum of a quantum dot photoconductive cell were detected. Room temperature photo-sensing properties were investigated under an irradiation of 3.39 μm as well. At a power density of 0.07 W cm⁻², the surface resistance of quantum dot PCC was reduced by up to 7 %. A current responsivity of 0.2 mA W⁻¹ was measured at an applied voltage of 8 mV.