Abstract
A Thermoelectrically Coupled Nanoantenna (TECNA) consists of a metallic antenna integrated with a thermoelectric junction. In its simplest form, a dipole antenna (∼λ/2 long) lies at the junction of two leads having different Seebeck coefficients. When radiation is absorbed by the antenna, the excited currents produce Joule heating that is transferred to the junction, generating an unbiased open-circuit voltage. Nanofabrication, specifically e-beam lithography, allows conventional microwave engineering to be scaled to mid/long-wave infrared and THz frequencies. The antenna allows the device to be engineered to respond to specific wavelengths and polarizations. At resonance, the effective absorption aperture of the antenna significantly exceeds its very small physical area. The subsequent small thermal mass results in measured bandwidths greater than 100 kHz. Understanding and engineering the thermal transport over nanoscale (50 × 100 × 7000 nm) leads is critical to improving device performance. This paper analyzes the thermal transport for dipole antennas suspended above hemispherical cavities. These cavities are etched into the substrate and provide thermal isolation to the antenna and feed structure, significantly improving the results. A frequency domain solution is driven by finite element analyzed absorption models in the antenna. These simplified models agree well with experiments using a CO2 laser. The modeled results are used to estimate an effective convection coefficient in air at this length scale. They are also analyzed to create design rules, including thermal transport for future devices.
