Optical characteristics of one-dimensional Si∕SiO2 photonic crystals for thermophotovoltaic applications

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 (TPV) devices. The crystals being investigated have a ten-layer quarter-wave periodic structure, and are based on Si∕SiO2 and Si∕SiON material systems. For TPV applications the crystals are designed to act as filters, transmitting photons with wavelengths below 1.78μm to a GaSb photodiode, while reflecting photons of longer wavelengths back to the source of thermal radiation. In the case of the Si∕SiO2 structure, the Si and SiO2 layers were designed to be 170 and 390nm thick, respectively. This structure was fabricated using low-pressure chemical vapor deposition. Reflectance and transmittance measurements of the fabricated Si∕SiO2 photonic crystals were taken from 0.8to3.3μm for both polarizations and for a range of incident angles. Measurement results were found to correlate well ...