17% efficiency heterostructure solar cell based on p-type crystalline silicon

In this work we describe in detail the process used to obtain high efficiency amorphous/crystalline silicon heterostructure solar cells, based on p-type crystalline silicon, typically used in cast production. The back side contact and very effective back surface field have been obtained by a screen printing process. An amorphous silicon intrinsic buffer layer and a n-type amorphous emitter have been deposited on the top of the wafer. A particular treatment has been performed on the top of the n layer in order to increase the conductance and reduce the activation energy of the layer. Finally a silver grid and an antireflection coating are deposited on the top of the device. With the aid of a numerical model, able to describe in detail the role of defect density at the heterojunction and the transport mechanism in the whole structure we analyze the photovoltaic performance. The current-voltage characteristic under AM1.5 and the quantum efficiency on 2.25 cm(2) sample have been reported. An efficiency of 17% is achieved that represents the highest result obtained on heterostructure solars cell based on p-type crystalline silicon. (C) 2004 Elsevier B.V. All rights reserved.