By analyzing the main recombination mechanisms in GaInAsSb materials, the dependences of the dark current density and open circuit voltage in n+-p GaInAsSb thermophotovoltaic cells on the recombination parameters, carrier concentration and cell thickness are calculated. The results show that the dark current mainly comes from p-region, and it is related with the surface and Auger recombinations in low and high carrier concentration ranges, respectively. The surface and Auger recombinations can be suppressed by reducing the surface recombination velocity and carrier concentration, respectively. The dark current density can be suppressed by optimizing material parameters and device surface passivation technique. So the high open circuit voltage can be obtained for GaInAsSb thermophotovoltaic cells.
