Abstract
In this study, as a novel approach to thin-film solar cells based on tin sulfide, an environmentally friendly material, we attempted to fabricate (Ge, Sn)S thin films for application in multi-junction solar cells. A (Ge(0.42) Sn(0.58))S thin film was prepared via co-evaporation. The (Ge(0.42) Sn(0.58))S thin film formed a (Ge, Sn)S solid solution, as confirmed by X-ray diffraction (XRD) and Raman spectroscopy analyses. The open circuit voltage (V(oc)), short circuit current density (J(sc)), fill factor (FF), and power conversion efficiency (PCE) of (Ge(0.42) Sn(0.58))S thin-film solar cells were 0.29 V, 6.92 mA/cm(2), 0.34, and 0.67%, respectively; moreover, the device showed a band gap of 1.42-1.52 eV. We showed that solar cells can be realized even in a composition range with a relatively higher Ge concentration than the (Ge, Sn)S solar cells reported to date. This result enhances the feasibility of multi-junction SnS-system thin-film solar cells.