van der Waals Interaction-Induced Tunable Schottky Barriers in Metal-2D Perovskite Contacts

We systematically study the bonding and electronic properties of metalBA2PbI4 contacts, which play a crucial role in affecting the device performance, based on density functional theory calculations. Tunable Schottky barrier heights (SBHs) are observed in metal-BA(2)PbI(4) contacts by using different metals with a moderate Fermi level pinning (FLP) effect. An interfacial van der Waals interaction-induced Pauli-exclusion effect is found to be responsible for the FLP. The unique structure of BA(2)PbI(4) ensures the interfacial interaction has a limited influence on the band energy of BA(2)PbI(4), since the spacer cation can be seen as a naturally formed buffer layer. We also found the SBHs depend on the thickness of inorganic layers in quasi-two-dimensional (2D) BA(2)MA(n-1)Pb(n)I(3n+1). A high tunneling barrier and low interfacial charge density are also observed in all contacts. The thorough understanding of the underlying mechanisms of bonding and electronic properties in these contacts is beneficial for us to promote the performance of 2D perovskite-related devices.

Automated summary

The study found that the tunable Schottky barrier heights in metal-BA2PbI4 contacts can be adjusted by using different metals with a moderate Fermi level pinning effect, and the interfacial van der Waals interaction-induced Pauli-exclusion effect is responsible for the Fermi level pinning. The unique structure of BA2PbI4 ensures limited influence of interfacial interaction on its band energy.