Multicrystalline Silicon Thin Film Solar Cells Based on Laser Crystallized Layers on Glass

Multicrystalline silicon thin film cells were prepared by the LLC (layered laser crystallization) process on a glass superstrate. In this process an a-Si layer is crystallized by a cw laser resulting in a seed layer with grains exceeding 100 mum in size. Subsequently this seed layer is epitaxially thickened by simultaneous deposition of a-Si and crystallization by repeated pulses of an excimer laser. Then a phosphorus doped emitter is added. In this paper cells which are prepared by a single chamber PECVD laboratory type process are compared to devices prepared by an industrially relevant multi-chamber process based on high power diode laser crystallization and high rate electron beam evaporation, respectively. Crystallization with the diode laser resulted in significantly larger grains. However, solar cell performance does not quite reach the values of cells prepared by the laboratory process