Progress in a-Si:H / c-Si heterojunction emitters obtained by Hot-Wire CVD at 200 oC

In this work, we investigate heterojunction emitters deposited by Hot-Wire CVD on p-type crystalline silicon. The emitter structure consists of an n-doped film (20 nm) combined with a very thin intrinsic hydrogenated amorphous silicon buffer layer (5 nm). The microstructure of these films has been studied by Spectroscopic Ellipsometry in the UV-visible range. These measurements reveal that the microstructure of the ndoped film is strongly influenced by the amorphous silicon buffer. The Quasy-SteadyState Photoconductance (QSS-PC) technique allows estimating implicit open-circuit voltages near 700 mV for heterojunction emitters on p-type (0.8 cm) FZ silicon wafers. Finally, 1 cm 2 heterojunction solar cells with 15.1 % conversion efficiency (total area) have been fabricated on flat p-type (14 cm) CZ silicon wafers with aluminum back-surface-field contact.