Modeling of graphene wrapped indium antimonide nanowire as thermo-optical waveguide

Abstract In this research work, the fiber modes supported by the graphene-wrapped indium antimonide nanowire have been examined theoretically. The indium antimonide (InSb) is a semiconductor material, which has temperature-sensitive optoelectronic properties. To model the nanowire of InSb, Drude’s model has been used for better results. The Kubo’s formalism based on the random phase approximation is used for the modeling of graphene. The impedance boundary conditions (IBCs) are used to compute the characteristic equations. The real and imaginary part of permittivity of InSb as function of THz frequency under different values of temperature <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>T</mml:mi> <mml:mo>∈</mml:mo> <mml:mo stretchy="false">[</mml:mo> <mml:mn>200</mml:mn> <mml:mspace width="0.5em"/> <mml:mi mathvariant="normal">K</mml:mi> <mml:mo>,</mml:mo> <mml:mspace width="0.25em"/> <mml:mn>400</mml:mn> <mml:mspace width="0.5em"/> <mml:mi mathvariant="normal">K</mml:mi> <mml:mo stretchy="false">]</mml:mo> </mml:math> has been computed. It is reported that the InSb shows the temperature dependent metal-insulator phase transition i.e., for temperature T ≤ 200 K it behaves as insulator and for T &gt; 200 K it acts as metal. The numerical results for dispersion relation, propagation band, propagation losses, cut off frequency range, effective mode index and field profiles have been presented for insulator as well as metallic phase of InSb. Moreover, the impact of chemical potential, radius, and temperature on fiber mode characteristics has been analyzed. The computed numerical results can be applied for designing tunable temperature assisted nano waveguides, thermo-optical sensing probes, thermal imaging and near-field communication devices in THz frequency range.