Mercury Cadmium Telluride (Hg1–xCdxTe) stands out as the predominant material for developing infrared (IR) detectors. In this chapter, the two-dimensional (2D) p-n (single homojunction and single heterojunction) and p-i-n (dual-heterojunction) architecture models of p+-Hg0.7783Cd0.2217Te/n–-Hg0.7783Cd0.2217Te, p+- Hg0.69Cd0.31Te/n–-Hg0.7783Cd0.2217Te, and n+-Hg0.68Cd0.32Te/n–- Hg0.7783Cd0.2217Te/p+-Hg0.7783Cd0.2217Te are proposed in long-wavelength infrared (LWIR) spectral region. The detectors are designed and analyzed for various optoelectronic characteristic parameters. The outcomes achieved through the Silvaco Atlas TCAD software are compared with those derived from analytical expressions and are found to agree with the analytical results. The proposed detectors are well-suited for their functioning at a wavelength of 10.6 μm under the condition of liquid nitrogen temperature (77 K). The single homojunction-based detector shows an external quantum efficiency (QEext) of 58.29%, a 3-dB cut-off frequency (f3-dB) of 104 GHz with a response time of 3.3 ps, whereas the heterojunction-based detector exhibits a QEext of 67.6%, a f3-dB of 265 GHz with a response time of 1.3 ps, and least dark current density. On the other hand, a dual-junction-based detector exhibits a QEext of 84.92%, a f3-dB of 1.28 THz with a response time of 0.27 ps, further confirming the suitability of the proposed dual-junction detector for low-noise operations.
Keywords: Cut-off frequency, Dark current, Detectivity, HgCdTe, Heterojunction, homojunction, Noise current, Photocurrent, Photodetector, Quantum efficiency, Response time, Responsivity, Spectral response.
