Dark and photoelectric conversion properties of p-MgPc/n-Si (Organic/Inorganic) heterojunction cells.

Abstract

Heterojunction cells of p-MgPc/n-Si have been fabricated by thermal evaporation of MgPc thin films onto Si〈100〉 single crystal wafers. The devices exhibit strong photovoltaic characteristics with an open–circuit voltage of 0.35 V, a short–circuit current of 3.57 mA and a power conversion efficiency of 1.05%. These parameters have been estimated at room temperature and under a monochromatic illumination of 633 nm with an input power density of 50 mW/cm 2. The activation energy of the charge carriers of 0.32 eV and the cell series resistance of 2 kΩ have been evaluated from the measurements of the dark I– V characteristics. A free–carrier concentration of 2.2×10 16 cm −3 and a barrier width of 75 nm have been estimated from C– V measurements. The temperature dependence of photocurrent, at constant illumination, has been also investigated.