Institute Silicon Photovoltaics
Hetero-junction interface
The hetero-interface is the crucial factor of a hetero-junction. This interface is characterized by lattice mismatch, interface states, band-offsets and band bending. These parameters influence the charge transfer across this interface and the interface recombination.
Often, interface recombination across a hetero interface (exemplarily sketched for the case of a wafer based a-Si/c-Si solar cell) is the main loss mechanism in heterojunction solar cells. Therefore we develop specific measurement methods in order to determine the physical parameters of the heterojunction interface and to quantify interface recombination, i.e.:
The Surface Photovoltage (SPV) method for measuring
- effective recombination time constants of the absorber: τeff
- band bending within the absorber: q·Φbic-Si
- interface defect state density: Dit(E)
