Temperature dependent spectral response characteri- stic of III-V compound tandem cell

The GaInP/GaAs/Ge triple-junction tandem cells with a conversion efficiency of 27.1% were fabricated using metalorganic chemical vapor deposition (MOCVD) technique. Temperature dependence of the spectral response measurements of the GaInP/GaAs/Ge tandem cell was performed by a quantum efficiency system at temperatures ranging from 25°C to 160°C. The red-shift phenomena of the absorption limit for all subcells were observed with increasing temperature, which is dued to the energy gap narrowing with temperature. The short-circuit current densities (J sc) of GaInP, GaAs and Ge subcells at room temperature calculated based on the spectral response data were 12.9, 13.7 and 17 mA/cm2, respectively. The temperature coefficient of J sc for the tandem cell was determined to be 8.9 μA/(cm2 · °C), and the corresponding temperature coefficient of the open-circuit voltage deduced from the series-connected model was 6.27 mV/°C.