Electrical contacts to monolayer black Phosphorus: a first principles investigation

TL;DR

This study uses first principles calculations to identify optimal metal contacts for monolayer black phosphorus, highlighting Cu(111) as the best candidate for forming ideal Ohmic contacts.

Contribution

The paper provides a detailed theoretical analysis of metal-BP contacts, identifying Cu(111) as the most suitable metal surface for low-resistance electrical contact.

Findings

Cu(111) forms the best Ohmic contact with BP.

Ta and Nb strongly bond causing bond distortions.

Other metals form Schottky contacts.

Abstract

We report first principles theoretical investigations of possible metal contacts to monolayer black phosphorus (BP). By analyzing lattice geometry, five metal surfaces are found to have minimal lattice mismatch with BP: Cu(111), Zn(0001), In(110), Ta(110) and Nb(110). Further studies indicate Ta and Nb bond strongly with monolayer BP causing substantial bond distortions, but the combined Ta-BP and Nb-BP form good metal surfaces to contact a second layer BP. By analyzing the geometry, bonding, electronic structure, charge transfer, potential and band bending, it is concluded that Cu(111) is the best candidate to form excellent Ohmic contact to monolayer BP. Other four metal surfaces or combined surfaces also provide viable structures to form metal/BP contacts, but they have Schottky character.