Carriers transport and electric field distribution in CdS-CdTe ferroelectric-semiconductor coupled solar cell

CdS-CdTe Ferroelectric-Semiconductor coupled (FSC) solar cell is a novel concept of photovoltaic device, with ferroelectric nano particles with wurtzite structure (CdS) embedded in light-absorbing semiconductors with zinc blend structure (CdTe). In this work, we found the non-conductive grain boundaries (GBs) as well as the current distribution adjacent to the GBs but circumventing them. Meanwhile, strong piezoelectric response has been observed at the non-conductive GBs of the FSC film, which is most likely S-rich CdS
_1-x
Te
_x
in wurtzite structure. The distribution of the electric field along the lateral direction is derived from the surface potential acquired through scanning Kelvin probe microscopy. More importantly, the distribution of the piezoelectric response domains and potential and lateral fields on the film surface indicates a causal relation between the piezoelectric GBs and the electric field on the film surface.