The Theoretical Performance of GaInAsSb and GaSb Cells Versus IR Emitter Temperature in Thermophotovoltaic Systems

Abstract

GaInAsSb cells may show better performance than GaSb cells in low-temperature thermophotovoltaic systems due to their lower bandgap energies. In this paper, numerical simulation is used to evaluate GaInAsSb and GaSb cells with similar structures under different radiation temperatures. We find that GaInAsSb cells with n-type emitters show slightly higher output power densities compared with those for GaSb cells with n-type emitters below 1500 K given-blackbody radiation, but the power density of the GaSb cells will surpass the former's above this temperature point. Furthermore, over the temperature range of 1200~2000 K, the efficiencies of GaSb cells with n-emitters are 1.31~2.32 times higher than those of GaInAsSb cells with n-emitters if filters with 10% subbandgap losses are used. Several parameters that affect the GaInAsSb cell were analyzed, such as doping profiles, thicknesses of GaInAsSb epitaxial layer and surface recombination velocity. The n-on-p junctions, i.e., n-type emitters vs p-type emitters are better for GaInAsSb cell fabrication, which is similar to that for the GaSb cell.