This paper presents theory, design, fabrication, and optical characterization of two-dimensional (2D) tungsten (W) photonic crystals (PhC) as selective thermal emitters. We use the photonic band gap of a 2D W PhC, radiating out of a plane of periodicity, to design a selective infrared thermal radiation source that exhibits close to blackbody emittance near the the band gap wavelength and relatively sharp cutoff for wavelengths above the band gap. In addition, we present simple design rules and detailed simulation results for several representative geometries. Microfabrication steps are also presented. Finally, we present detailed experimental results of the optical characterization of three fabricated prototypes that exhibit good agreement with simulation results.

This article presents a detailed exploration of the optical characteristics of various one-dimensional photonic crystal structures designed for use as a means of improving the efficiency and power density of thermophotovoltaic ͑TPV͒ devices. The crystals being investigated have a ten-layer quarter-wave periodic structure, and are based on Si/ SiO 2 and Si/ SiON material systems. For TPV applications the crystals are designed to act as filters, transmitting photons with wavelengths below 1.78 m to a GaSb photodiode, while reflecting photons of longer wavelengths back to the source of thermal radiation. In the case of the Si/ SiO 2 structure, the Si and SiO 2 layers were designed to be 170 and 390 nm thick, respectively. This structure was fabricated using low-pressure chemical vapor deposition. Reflectance and transmittance measurements of the fabricated Si/ SiO 2 photonic crystals were taken from 0.8 to 3.3 m for both polarizations and for a range of incident angles. Measurement results were found to correlate well with simulation results for the ideal structure. Measurement results were used to predict the TPV system efficiency, power density and spectral efficiency using an ideal thermodynamic model of a TPV system.

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