Extending the operational wavelength of thermophotovoltaic devices via superlattice and barrier engineering

In this paper, we investigate extending the operational wavelength of thermophotovoltaic diodes. Our calculations demonstrate that employing a barrier structure can reduce the diffusion current by several orders of magnitude, reducing dark current and improving the overall function of the TPV diode for room temperature operation. We first investigated GaSb/InAs type–II superlattice structures with monovalent barriers targeting wavelength cut-offs of five microns. Simulations were used to optimize the band structure energy levels for superlattice materials and to align the energy bands between different layers in the device. We examine the difference in IV curves between barrier and non-barrier structures for a five micron (Eg=0.248 eV) diode with a barrier of 300 meV.