Innovative design of amorphous/crystalline silicon heterojunction solar cell

In this work we show how the heterostructure technology can have a chance in the challenge of interdigitated back contact solar cell. We present an innovative rear junction, backside contact design in which both the emitter and the back surface field are formed by amorphous/crystalline silicon heterostructure, and the grid-less front surface is passivated by a double layer of amorphous silicon and silicon nitride, which also provides a good anti-reflection coating. The technological processes are performed at temperature below 300 °C with the aid of one metallic mask to create the interdigitated pattern. The initials results, on a p-type monocrystalline silicon wafer; are really promising, a Voc of 687 mV has been reached. We show that the uniformity of the deposited amorphous silicon layers is not influenced by the mask-assisted deposition process and that the alignment is feasible. On the other hand several technological aspects that strongly limit the fill factor (50%) and the short circuit current density (30 mA/cm2) have to be optimized.