Exploring Performance of Metamaterial Emitters for Applications of Energy Harvesting and Gas Sensing: Modeling and Simulation Approach

Abstract

This dissertation presents a theoretical investigation into the spectral performance of a multilayer and grating metamaterial composed of tungsten (W) and Aluminumnitride (AlN), hafnium dioxide (HfO₂) designed to enhance thermophotovoltaic (TPV) energy conversion efficiency. Utilizing advanced electromagnetic simulations based on Maxwell‘ s equations, the study explores the optical properties of a W/HfO₂/W metamaterial structure, focusing on its ability to produce high emissivity within the wavelength range of 1.5 to 2.0 μm optimal for interfacing with InGaAsSb TPV cells. The results demonstrate that the metamaterial achieves an average emissivity exceeding 96%, with a peak of 99.9%, primarily driven by resonant mechanisms such as surface plasmon polaritons and magnetic polaritons. The design exhibits polarization independence and maintains high performance across incident angles of 0° to 60°, indicating robustness for practical applications. Furthermore, the study assesses the impact of material selection and structural parameters on emissivity characteristics, emphasizing the potential of engineered metamaterials to significantly improve thermal radiation control. The findings suggest that the proposed W/HfO₂/W metamaterial has promising implications for advancing high-efficiency TPV systems, contributing to sustainable energy solutions through optimized thermal emission engineering. Additionally, it presents the design and simulation of a terahertz metamaterial-based gas sensor aimed at detecting toxic atmospheric gases such as ozone (O₃) and nitric oxide (NO). Utilizing a metal-dielectric metal (MDM) structure composed of tungsten and hafnium dioxide, the sensor exhibits dual resonance frequencies with absorption rates approaching 99%. Finite Element Method (FEM) simulations demonstrate high sensitivity to variations in refractive index, with sensitivities up to 4.58 THz/RIU and a figure of merit exceeding 11.82/RIU. Distinct resonance shifts corresponding to different gases affirm the sensor‘s potential for real time, selective gas detection. The findings underscore the effectiveness of metamaterials in environmental monitoring applications and lay the groundwork for developing practical, hi gh-performance gas sensors for air quality assessment.