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Abstract— A promising technology for waste-heat recovery applications is thermophotovoltaics (TPVs), which use photovoltaic diodes to convert thermal energy into electricity. The most commonly used TPV diode material is gallium antimonide (GaSb). Recently, GaSb TPV diodes were fabricated with front-surface metallic photonic crystal (MPhC) filters to more optimally convert the incident spectrum. This method showed promising initial results, in part due to a shifting of the photogenerated carriers away from the front-surface and into the device. In this paper, we use the Atlas-Silvaco software package to optimize the TPV diode structure for MPhCs. We investigate the addition of an intrinsic region in the device to take advantage of the shifted photogeneration profile from the MPhCs. This design allows for a 10% improvement in internal quantum at the peak MPhC transmission wavelength. https://doi.org/10.1109/MWSCAS.2017.8053055 

Thermophotovoltaics (TPVs) are a potential technology for waste-heat recovery applications and utilize IR sensitive photovoltaic diodes to convert long wavelength photons (>800nm) into electrical energy. The most common conversion regions utilize Gallium Antimonide (GaSb) as the standard semiconductor system for TPV diodes due to its high internal quantum efficiencies (close to 90%) for infrared radiation (~1700nm). However, parasitic losses prevent high conversion efficiencies from being achieved in the final device. One possible avenue to improve the conversion efficiency of these devices is to incorporate metallic photonic crystals (MPhCs) onto the front surface of the diode. In this work, we study the effect of MPhCs on GaSb TPV diodes. Simulations are presented which characterize a specific MPhC design for use with GaSb. E-field intensity vs. wavelength and depth are investigated as well as the effect of the thickness of the PhC on the interaction time between the e-field and semiconductor. It is shown that the thickness of MPhC has little effect on width of the enhancement band, and the depth the ideal p-i-n junction is between 0.6􀈝m and 2.1um. Additionally, simulated results demonstrate an increase of E-field/semiconductor interaction time of approximately 40% and 46% for a MPhC thickness of 350nm and 450nm respectively.