Metamorphic and Lattice-Matched GaInP Rear-Heterojunction Solar Cells for Improved Performance at Elevated Temperatures

We present the characteristics of n -on- p front-junction (FJ) and rear-heterojunction (RHJ) GaInP solar cells at operating temperatures ( T ) up to 300 °C. Photovoltaic cells with efficient operation at high T may be important for satellite missions near the sun or as laser power converters for sensors operating in harsh environments. In this article, we show that the time-resolved photoluminescence lifetime ( <tex-math notation="LaTeX">τ TRPL</tex-math> ) values in both lattice-matched (LM) n -Ga 0.51 In 0.49 P and metamorphic (MM) n -Ga 0.37 In 0.63 P double heterostructures are high and increase significantly with T . In contrast, the <tex-math notation="LaTeX">τ TRPL</tex-math> values in their p -type counterparts are lower and decrease with T . We go on to demonstrate both LM and MM solar cells in FJ and RHJ configurations. The internal quantum efficiency (IQE) of MM RHJ cells increases significantly up to T = 300 °C due to the increase in both <tex-math notation="LaTeX">τ TRPL</tex-math> and the linear increase in diffusivity with T . In contrast, the IQE for MM FJ cells is nearly unchanged as T increases, while the IQE of LM cells drops sharply across all wavelengths. RHJ cells maintain higher open-circuit voltage and fill factor than their FJ counterparts, leading to a significant efficiency advantage at T = 100–300 °C. Taken together, our work shows that MM cells perform well at elevated T and that RHJ cells are promising for high- T operation.