CRYSTALLOGRAPHIC ANALYSIS AND SOLAR CELLS OF POLYSILICON FILMS FORMED BY ALUMINIUM INDUCED CRYSTALLIZATION

摘要

In this work, we compare structural and electrical properties of poly-Si solar cells formed on alumina and glass-ceramic substrates. The formation of poly-Si seed layers formed by aluminium induced crystallization (AIC) technique is followed by the epitaxial thickening, using low-pressure chemical vapor deposition (LPCVD). Intrinsic and n+ type amorphous silicon, respectively, were deposited on p-type epi-layer to form the heterojunction emitter based solar cells. The surface morphologies of the AIC seed layer and epi-layer were observed by optical microscope and electron backscattering diffraction (EBSD) techniques. The average grain size of AIC poly-Si layers increases up to 25.2μm by using glass-ceramic substrate while it is only 7.6μm for poly-Si films on alumina substrates. Furthermore the preferred orientation is <100> in both cases. Finally, the characteristics of poly-Si based solar cells were measured by using a solar simulator. The best devices show an efficiency of 3.3% for cells on glass-ceramic substrates and about 2.9% on alumina substrates. The reason for this difference will be discussed.