Low-temperature carrier transport and thermophotovoltaic performance of GaSb p–n homojunction

The performance of low-bandgap based semiconductor devices is strongly affected by operating temperature, making low temperature investigations relevant for thermophotovoltaic conversion, deep-space power systems, and infrared detection. While GaSb-based devices are technologically important, their operation at low temperatures remains insufficiently investigated. In this work, the influence of temperature on a GaSb p–n homojunction is investigated in the range of 150–300 K using two independent approaches. First, current density–voltage (J–V) characteristics extracted from current–voltage (I–V) curves reported in the literature are analyzed at 150, 200, 250, and 300 K under forward and reverse polarization. Under forward bias, shunt resistance, saturation current densities, and ideality factors are extracted using the Shockley diode method and a derivative-based technique. Under reverse bias, carrier transport mechanisms are identified through comparison with the well known theoretical models of minority-carrier diffusion, depletion-region generation, and band-to-band and trap-assisted tunneling. Second, the photovoltaic performance of the GaSb homojunction is investigated using the Solar Cell Capacitance Simulator (SCAPS-1D). Simulations include defect states as well as radiative and Auger recombination mechanisms. To evaluate device operation under thermophotovoltaic conditions, a 1500 K blackbody source in the 1–5 μm wavelength range is considered. The results reveal an improvement of the cell’s output parameters as temperature decreases. At 150 K, the open-circuit voltage and conversion efficiency reach 0.64 V and 37.86%, respectively, while the short-circuit current density remains nearly temperature-independent at approximately 47.9 mA cm −2 . These findings highlight the potential of low temperature operation for GaSb-based devices.