Effect of material parameters on the open-circuit voltage in a GaInAsSb thermophotovoltaic cell

Abstract

In this paper, a numerical simulation on the open-circuit voltage ( V OC ) of the P-GaSb window/ P-Ga 0.8In 0.2As 0.18Sb 0.82 emitter/ N-Ga 0.8In 0.2As 0.18Sb 0.82 base/ N-GaSb structure thermophotovoltaic (TPV) cell is performed and an analysis of the effects of device parameters on V OC is presented. The simulations are carried out with the fixed spectral control filter and for the radiator temperature of T rad = 950 °C, cell temperature of T dio = 27 °C, the radiation photons are injected from the front P-region. The thick P-Ga 0.8In 0.2As 0.18Sb 0.82 emitter with the longer minority carrier diffusion length is the main optical absorption region. The simulated results are compared with the available experimental data, and a good agreement is obtained. The effects of the layer thickness, carrier concentration, injection level and main recombination mechanisms (e.g. the radiative, Auger, bulk Shockley–Read–Hall (SRH) and surface recombination) of the P-Ga 0.8In 0.2As 0.18Sb 0.82 emitter and N-Ga 0.8In 0.2As 0.18Sb 0.82 base on V OC are analyzed. It indicates that the parameters of the emitter region have stronger effect than that of the base region on V OC . Dependence of V OC on the material parameters of P-GaSb window layer is also analyzed, both the carrier concentration and thickness of P-GaSb window layer have effect on V OC . Moreover, adding a back surface reflector (BSR) to the TPV cell can increase V OC .