Thermally Active Plasmonic Modes in Black Phosphorus Coated Semiconductor Nanowire

Tunable Plasmonic modes have applications is sensing, computing, imaging, waveguides, filters, modulators and communication systems. In present work, the theoretical investigation on the temperature assisted tunability of the plasmonic-polaritonic modes supported by the black phosphorus (BP) coated temperature sensitive semiconductor nanowires has been carried out. The Indium Antimonide (InSb) has been taken as temperature sensitive semiconductor nanowire. The anisotropic conductivity of the BP layer was modeled using the random phase approximation (RPA) based semiclassical model for the armchair (AC) and zigzag (ZZ) orientations, while the extended Drude model was used to model the temperature-dependent dielectric constant of InSb. The dispersion curve, effective mode index (EMI), normalized phase speed, propagation loss and field distribution has been computed for the AC and ZZ plasmonic modes of BP. The influence of temperature and surface charge concentration on the plasmonic interactions for each configuration has been analyzed. Furthermore, a comparative analysis reveals that, for InSb at T = 240 K (insulating state), the plasmonic resonance frequency lies in the lower terahertz frequency range (0.1–1 THz), whereas at T = 400 K (metallic state), it shifts to the higher terahertz frequency range (5–6 THz). The plasmonic modes in ZZ orientation exhibits stronger response than the AC orientation. The numerical results demonstrate that the BP-coated InSb nanowire offers dual tunability of the guided plasmonic modes, with potential applications in the design of reconfigurable THz plasmonic waveguides, compact integrated photonic circuits, and actively tunable sensing devices.