Add-on laser tailored selective emitter solar cells

An elegant laser tailoring add-on process for silicon solar cells, leading to selectively doped emitters increases their efficiency eta by Delta eta = 0.5% absolute. Our patented, scanned laser doping add-on process locally increases the doping under the front side metallization, thus allowing for shallow doping and less Auger recombination between the contacts. The selective laser add-on process modifies the emitter profile from a shallow error-function type to Gaussian type and enables excellent contact formation by screen printing, normally difficult to achieve for shallow diffused emitters. The significantly deeper doping profile of the laser irradiated samples widens the process window for the firing of screen printed contacts and avoids metal spiking through the pn-junction. Copyright (C) 2010 John Wiley & Sons, Ltd.