# Plasmonically Enhanced Reflectance of Heat Radiation from Low-Bandgap Semiconductor Microinclusions

## TL;DR

This study explores how plasmonic resonances in low-bandgap semiconductor microinclusions can significantly enhance infrared reflectance in composites, reducing thermal radiation losses at high temperatures.

## Contribution

It demonstrates the potential of using low-bandgap semiconductor microinclusions to tailor infrared reflectance and minimize radiative thermal losses in high-temperature insulators.

## Key findings

- Achieved 57-65% reflectance with Si and Ge microinclusions.
- Identified optimal particle sizes and materials for maximum reflectance.
- Observed broadband reflectance spectra due to defect-induced charge carriers.

## Abstract

Increased reflectance from the inclusion of highly scattering particles at low volume fractions in an insulating dielectric offers a promising way to reduce radiative thermal losses at high temperatures. Here, we investigate plasmonic resonance driven enhanced scattering from microinclusions of low-bandgap semiconductors (InP, Si, Ge, PbS, InAs and Te) in an insulating composite to tailor its infrared reflectance for minimizing thermal losses from radiative transfer. To this end, we compute the spectral properties of the microcomposites using Monte Carlo modeling and compare them with results from Fresnel equations. The role of particle size-dependent Mie scattering and absorption efficiencies, and, scattering anisotropy are studied to identify the optimal microinclusion size and material parameters for maximizing the reflectance of the thermal radiation. For composites with Si and Ge microinclusions we obtain reflectance efficiencies of 57 - 65% for the incident blackbody radiation from sources at temperatures in the range 400 - 1600 {\deg}C. Furthermore, we observe a broadbanding of the reflectance spectra from the plasmonic resonances due to charge carriers generated from defect states within the semiconductor bandgap. Our results thus open up the possibility of developing efficient high-temperature thermal insulators through use of the low-bandgap semiconductor microinclusions in insulating dielectrics.