Simplified Interdigitated Back Contact Solar Cells

In this work, the fabrication of an interdigitated back contact solar cell is investigated on p-type Czochralski silicon wafers using a novel laser doping approach to form both polarities of rear contacts. Using only one conventional thermal diffusion which forms the n+ active emitter on the rear and n+ floating emitter on the front of the device, implied open circuit voltages exceeding 690 mV have been achieved on partly processed devices prior to metallisation, with virtually full-area emitter coverage and both polarities of contacts formed, indicating the potential of this structure for achieving high efficiencies with a simple process. Severe shunting post-metallisation due to the poor electrical isolation properties of the rear surface passivation layer currently limits the final device voltage to 625 mV. Further investigations must be undertaken in order to minimise the parasitic shunting effect and maintain a high open circuit voltage post-metallisation.