Revealing the Role of Phosphorus Modification in Pt-Based Nano- and Micro-Electromechanical Contacts

Abstract

Platinum is a promising contact candidate for electronic devices in micro-/nano-electromechanical systems (MEMS/NEMS) due to its conductivity and stability under high temperatures, chemical attack, and mechanical stress. However, its effectiveness is challenged by the high cost of Pt and the inevitable tribopolymer formation on Pt surfaces during the rigorous mechanical cycling of switches. In this work, we propose to decorate Pt contacts with non-metallic elements such as phosphorus (P), which improves the thermomechanical efficiency by modifying the electronic structure and chemical reactivity of the contact. A systematic density functional theory (DFT) study was performed to demonstrate that P dopants on the Pt(111) surface are both thermodynamically and kinetically favorable. In addition, a thin oxide layer is likely to form on the P-modified Pt contacts, which will act as a protective layer in order to prevent bulk oxidation and decrease tribopolymer formation due to benzene degradation. Our results imply that the P-modified Pt(111) contact is promising for MEMS/NEMS devices and offers a perspective for materials design in electronic device applications.