Schottky-type edge passivation of silicon solar cells

Abstract

We investigated Schottky-type edge passivation of Si solar cells using Ag nanodots and the enhancement of cell conversion efficiency by improving the fill factor. The threshold voltage for the termination of photocurrent is increased by about 0.13V compared to the reference sample without edge passivation. The cross-section of the pn junction depletion region forms an Ag/Si Schottky contact in the depletion layer of the space and the image charges with a width of about 28nm. However, the p- and n-electrodes form Ohmic contacts with a contact depletion width of less than 5nm for the carrier tunneling process. The edge Schottky contact reduces the carrier recombination and saturation current at the surrounding edge region and enhances the fill factor and the pn junction property with increased shunt resistance, indicating that metallic edge passivation is an important process for large-scale Si solar cell fabrication.