Temperature dependent spectral response characteristic of Ⅲ-Ⅴ compound tandem cell

The GalnP/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 GalnPIGaAslGe tandem cell was performed by a quantum efficiency system at temperatures ranging from 25℃ to 160℃. 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 （Jsc） of GalnP, GaAs and Ge subcells at room temperature calculated based on the spectral response data were 12.9, 13.7 and 17 mA/cm^2, respectively. The temperature coefficient of Jsc for the tandem cell was determined to be 8.9 μA/（cm^2, ℃）, and the corresponding temperature coefficient of the open-circuit voltage deduced from the series-connected model was -6.27 mV/℃.