Ohmic Contact Effect of Ag-Nanodots on Quantum Efficiency of Si Solar Cell

Abstract

The authors investigated Si solar cell with the inclusion of nano-Ag dots using the ink-jet printer. These nano-Ag dots were used for the Ohmic contact layer on phospho-silicate glass layer, which was not removed after the formation of Si emitter layer by phosphorus diffusion process. The SiNx layer deposited on the nano-Ag dots shows the catalyst selective growth and so the layer formed beneath of nano-Ag dots. The photoreflectances show that the long wavelength from 360 nm to 1200 nm tends to be increased as the density of the nano-Ag is increased. In case of short wavelength from 294 nm to 367 nm, it shows the opposite trend, indicating the plasmon effect of the nano-Ag. As embedding the nano-Ag dots on the phospho-silicate glass layer, the blocked Ohmic contact was opened and the quantum efficiency of 14.4% was achieved, which is higher than the reference sample of 12.72% without the glass layer. The nano-Ag dots form the good Ohmic contact and also enhance the light conversion efficiency with the formation of surface plasmon.