Mid-infrared photodetectors based on quaternary InAsSbP nanostructures

Quaternary InAsSbP quantum dots (QD) with the surface concentration of (3-5)x10(9) cm(-2) have been grown on the InAs(100) substrate by the modified version of liquid-phase epitaxy. Morphology and distribution of densities of QDs were studied by means of atomic-force microscope. Diameter distribution of QDs was revealed to be Gaussian. The mean value of QD diameter is 23.1 nm with the variance of 6.9 nm. Two types of infrared photodetectors (IRPD) on the basis of InAs(100), with and without InAsSbP-QDs on the substrate surface, were fabricated and studied. Spectra of photoresponse of both types of IRPD at room temperature were measured and analyzed and a red shift was revealed for structures with QDs. Capacitance characteristics of IRPD and relative change in their surface resistance after irradiation with cw He-Ne laser have been studied.