Effect of edge junction isolation on the performance of laser doped selective emitter solar cells

Abstract

The effect of laser and chemical edge junction isolation on electrical performance of industrially manufactured laser doped selective emitter solar cells with light induced plated n-type contacts is investigated in this work. Directly after the formation of the aluminium back surface field, photoluminescence images indicates that laser edge junction isolation causes substantial damage around the perimeter of the cell, extending several millimeters from the laser edge isolation groove. On finished devices, regions of high series resistance are evident around the perimeter, caused by parasitic plating nucleating in the damaged laser grooved region which induce shunting and inhibits further plating taking place in the surrounding regions. The use of chemical edge junction isolation eliminates both of these issues and can result in efficiency gains of more than 2% absolute compared to that fabricated using laser edge isolation, suggesting a far superior method of edge junction isolation for the industrial manufacture of laser doped selective emitter solar cells with light induced plated contacts.