Copper (Cu) dopant as the hole enhancer for chemical bath deposited n-type FeSxOy for solar cells applications

Abstract

We performed a chemical bath deposition (CBD) to deposit copper (Cu)-doped iron-sulfide-oxide (FeS_xO_y). Higher copper concentration reduced transmittance, the direct bandgap, and oxygen content, while increasing the formation of flower-like agglomerations on the surface. Cu acted as a hole enhancer, lowering the oxygen character in the n-type (electron-dominant) FeS_xO_y, thereby obtaining p-type (hole-dominant) behavior when the Cu concentration was ≥ 2.4 mM. In this work, we systematically observed the effect on the physicochemical properties and photovoltaic properties by changing the concentration (0–7.2 mM) of Cu in the bath solution. P-type Cu-doped FeS_xO_y/n-type FeS_xO_y heterojunctions exhibited rectification properties in a current density-voltage (J-V) measurement.