Interface Energy-Level Alignment between Black Phosphorus and F16CuPc Molecular Films

Abstract

The organic/inorganic semiconductor interfaces play a key role in determining the functionality of charge injection devices. The energy-level alignment at the interfaces between two in-plane organic materials (F16CuPc and CuPc) and single-crystal black phosphorus was systematically studied by in situ ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS). In this work, we reveal that the deposition of F16CuPc onto black phosphorus surface leads to a considerable charge transfer across the interface, resulting in the pronounced increment of work function. As for the molecule–substrate interaction, both F16CuPc and CuPc interact with black phosphorus via van der Waals physisorption, as confirmed by the UPS and XPS measurements. Our results demonstrate the versatile use of organic molecules to tailor the energy levels of black phosphorus based hybrid structures, which can be potentially used to optimize its function in future devices.