A robust SmartSilicon technology for a-Si:H heterojunction cells on MG and UMG-Si with efficiencies in the 16–18% range

We have developed a manufacturing- and field-worthy technology based on low cost p-type MG and n-type UMG active absorbers. By optimizing the casting process, we are able to achieve good carrier mobility. The cell is then enabled with a-Si:H for the surface passivation, emitter, back surface field and back reflector. The efficiencies are close to mainstream diffused junction cells, but with a much lower thermal coefficient of efficiency and 70~75% lower energy budget. Moreover the emitter current distribution is largely independent of underlying defects in the MG-Si. Hence the cells can be scaled to larger wafer sizes with cost benefits previously seen for semiconductors and flat-panel LCD´s.