Multiinterface Si solar cells with active substructures and active interfaces

The multiinterface concept seems allow a considerable increase of the present efficiency limit of Si solar cells. An experimental investigation of several types of multiinterface Si structures obtained, for example, by impurity implantation and adequate thermal treatment has been carried out. The most characteristic feature of the devices investigated concerns a buried amorphized substructure which is delimited at its front and back edges by a-Si/c-Si heterointerfaces. Electron microscope and X-ray studies show that these two phases are separated by a very sharp interface and a very thin c-Si transition zone with new crystalline properties. In this way, active substructures and active interfaces can be well-controlled by bandgap, defect and stress engineering. The results obtained indicate one of the possible ways towards the practical realization of improvements postulated by theory and simulations.