Effect of Silicon Front Surface Doping Profile on GaP/Si Heterostructure for III-V/GaP/Si Multi-junction Solar Cells

For optimizing III-V/GaP/Si tandem cells, test samples are fabricated featuring an epitaxial GaP layer on top of p-type front junction and n-type rear junction silicon cells. The device characterization results are used to calibrate our Sentaurus model and the interface recombination velocity between GaP and Si is found to be 5 × 10⁴cm/s by fitting the EQE data. To achieve a better spectral response for the silicon bottom cell, numerical simulation indicates that the GaP/p-Si cell prefers a shallow front junction depth within 0.25 μ m while the GaP/n-Si cell requires an intermediate junction depth of 2-4 μ m.