Decreasing dark current in long wavelength InAs/GaSb thermophotovoltaics via bandgap engineering

Abstract

At present, the state of the art thermophotovoltaic diode material is GaSb, with a bandgap of 0.7 eV corresponding to source temperatures greater than 1000°C. We investigate alternative bandstructure designs using the InAs/GaSb superlattice material system, which enable shorter bandgaps corresponding to lower source temperatures. For an InAs/GaSb superlattice system, we examine the effect of a monovalent barrier inserted between the p and n-doped regions. Through simulations, with the program Silvaco, we demonstrate that this barrier decreases the dark current and increases the open-circuit voltage, improving the overall power output and, thus, extending the operational wavelength of thermophotovoltaics.