Black phosphorus nanosheets in field effect transistors with Ni and NiCr contacts

We report the fabrication and electrical characterization of multi-layer black phosphorus-based field-effect transistors with Ni or NiCr alloy contacts. The devices show p-type conduction and hysteresis in the transfer characteristics that enables their use as non-volatile memories. We investigate the differences between Ni and NiCr contacts and apply the Y-function method to extract channel mobility up to 112 cm2V−1s−1 and the contact resistances. Ni contacts present specific contact resistance of 6.3 kΩ μm that increases to 18.1 kΩ μm for NiCr. Our findings are important for the technological exploitation of multi-layer BP in a new class of electronic and optoelectronic devices.