Dielectric/metal/dielectric structures using copper as metal and MoO3 as dielectric for use as transparent electrode

Transparent conductive oxide/metal/oxide, where the oxide is MoO3 and the metal is Cu, is realized and characterized. The films are deposited by simple joule effect. It is shown that relatively thick Cu films are necessary for achieving conductive structures, what implies a weak transmission of the light. Such large thicknesses are necessary because Cu diffuses strongly into the MoO3 films. We show that the Cu diffusion can be strongly limited by sandwiching the Cu layer between two Al ultra-thin films (1.4 nm). The best structures are glass/MoO3 (20 nm)/Al (1.4 nm)/Cu (18 nm)/Al (1.4 nm)/MoO3 (35 nm). They exhibit a transmission of 70% at 590 nm and a resistivity of 5.0 · 10− 4 Ω cm. A first attempt shows that such structures can be used as anode in organic photovoltaic cells.

► MoO3/Cu/MoO3 structures are probed as transparent electrode.
► A strong Cu diffusion into the MoO3 is observed.
► Cu diffusion can be reduced by sandwiching the Cu layer between two ultra thin Al films.
► Organic solar cells using this structure have been probed.