Enhanced optoelectronic properties of a mercury cadmium telluride based double heterojunction photodetector for terahertz applications

There is a need for the development of photodetectors that can yield very low dark currents and good optical characteristics for terahertz applications. In this paper, to achieve low dark current and enhanced optical characteristics, a HgCdTe based double heterojunction n-i-p photodetector operating at 30 µm has been proposed. The photodetector designed is simulated in the ATLAS™ TCAD tool and the results obtained are further validated through analytical modeling. The device has been operated at a temperature of 77 K. The studies on the double heterojunction photodetector reveals the enhancement in the optoelectronic properties in comparison to the single hetero-junction photodetector. From the results, the dark current is found to be of the order of 2.42×10−10A, quantum efficiency (ɳ) ~75.35%, responsivity (R) ~18.21 A/W, specific detectivity (D*) ~1.99×109mHz1/2W−1 and noise equivalent power (NEP) ~0.21×10−16W.