Interface Study of ITOZnO and ITOSnO2 Complex Transparent Conductive Layers and Their Effect on CdTe Solar Cells

Abstract EN

Transparent ITO/ZnO and ITO/SnO2 complex conductive layers were prepared by DC- and RF-magnetron sputtering.

Their structure and optical and electronic performances were studied by XRD, UV/Vis Spectroscopy, and four-probe technology.

The interface characteristic and band offset of the ITO/ZnO, ITO/SnO2, and ITO/CdS were investigated by Ultraviolet Photoelectron Spectroscopy (UPS) and X-ray Photoelectron Spectroscopy (XPS), and the energy band diagrams have also been determined.

The results show that ITO/ZnO and ITO/SnO2 films have good optical and electrical properties.

The energy barrier those at the interface of ITO/ZnO and ITO/SnO2 layers are almost 0.4 and 0.44 eV, which are lower than in ITO/CdS heterojunctions (0.9 eV), which is beneficial for the transfer and collection of electrons in CdTe solar cells and reduces the minority carrier recombination at the interface, compared to CdS/ITO.

The effects of their use in CdTe solar cells were studied by AMPS-1D software simulation using experiment values obtained from ZnO, ITO, and SnO2.

From the simulation, we confirmed the increase of Eff, FF, Voc, and Isc by the introduction of ITO/ZnO and ITO/SnO2 layers in CdTe solar cells.