Progress in evaporated crystalline silicon thin-film solar cells on glass

Research is underway at UNSW aiming at the realization of efficient and inexpensive polycrystalline silicon (poly-Si) thin-film solar cells on glass. The idea behind the program is to significantly lower the cost of PV electricity by (i) making the solar cells from a thin film of crystalline silicon, (ii) using electron-beam evaporation for silicon deposition, (iii) using glass as the supporting material, and (iv) creating large-grained poly-Si absorber layers by means of a seed layer. We chose e-beam evaporation of silicon because it provides a much higher deposition rate than all other low-temperature Si deposition methods. Due to the inherent cost constraints of PV, we have limited our work from the outset to non ultra high vacuum conditions. So far, three different solar cells have been developed in the course of the program: EVA, ALICE and ALICIA. In this paper it is shown that good progress is being made towards efficient evaporated poly-Si thin-film solar cells on glass. From the results achieved so far it is already clear that silicon evaporation in a non-UHV environment is capable of producing device-grade poly-Si thin-films for solar cells. Interestingly, this conclusion applies to materials fabricated with each of the three approaches investigated by us (SPC, SPE, IAD).