Abstract: Based on the existing largescale solar cell production process, a series of sheet resistance emitters were prepared by changing diffusion process conditions. When the emitter sheet resistance increases, shortcircuit current rises continuously, and opencircuit voltage is close to saturation near 70 Ω/□, while fill factor (FF) declines due to the increase of serial resistance under the condition that other process parameters are unchanged. Efficiency of the device reaches maximum when the emitter sheet resistance is 70 Ω/□. Based on this conclusion, this paper compares gettering effect of the emitter sheet resistance between 50 and 70 Ω/□ by photoluminescence (PL) images. PL images show that during the diffusion process of phosphorus in a silicon grain, grain boundary and dislocation, gettering effect of these regions is very obvious, and the absorbing effect of the 50 Ω/□ emitter silicon is slightly better than the 70 Ω/□ one.

Key words: absorbing effect, diffusion, photoluminescence (PL), sheet resistance, solar cells