Microstructured tungsten thermophotovoltaic selective emitters c by Natalija (Zorana) Jovanović.

Abstract

This research investigates the fabrication, modeling, characterization, and application of tungsten two-dimensional (2D) photonic crystal (PhC) structures as selective emitters and means of achieving higher efficiencies in thermophotovoltaic (TPV) energy conversion systems. Important aspects of the fabrication process are researched, developed, and rigorously characterized, focusing on dimensional reliability, precision, and repeatability of the processes. A major contribution in the form of tungsten reactive ion etch (RIE) characterization is provided with detailed parameters and second-order influences on etch rate, smoothness, and mask erosion. Optical characterization of our prototypes is found to be in excellent agreement with simulation, and has provided an experimental confirmation of selective emitter performance. We show that selective emitters can substantially increase spectral efficiency, providing as much as three times the radiative power density of planar tungsten. We include the first measurement of 96% combined efficiency of a selective emitter and a dielectric stack mirror for TPV system applications.