Development of microcrystalline silicon carbide window layers by hot-wire CVD and their applications in microcrystalline silicon thin film solar cells

Microcrystalline silicon carbide (μc-SiC:H) thin films in stoichiometric form were deposited from the gas mixture of monomethylsilane (MMS) and hydrogen by Hot-Wire Chemical Vapor Deposition (HWCVD). These films are highly conductive n-type. The optical gap E04 is about 3.0–3.2 eV. Such μc-SiC:H window layers were successfully applied in n-side illuminated n-i-p microcrystalline silicon thin film solar cells. By increasing the absorber layer thickness from 1 to 2.5 μm, the short circuit current density (jSC) increases from 23 to 26 mA/cm2 with Ag back contacts. By applying highly reflective ZnO/Ag back contacts, jSC = 29.6 mA/cm2 and η = 9.6% were achieved in a cell with a 2-μm-thick absorber layer.