Structural and Electronic Properties of Metals (Al, Ti, Mo, and Zr) Terminated Diamond (100) Surfaces*

Diamond has exceptional structural, thermal, and electronic properties. Metals induce electronic properties such as negative electron affinity, thermal stability, and low contact resistance allowing charges to flow easily in between them. This is critical in the advancement of diamond- based devices, but no metal has previously been identified to make effective electrical contact with diamond. To begin addressing this issue surface reconstruction at the interface need to be explored. The goal of this study is to understand the surface chemistry of metals Aluminum (Al), Titanium (Ti), Zirconium (Zr), and Molybdenum (Mo) on diamond. In this presentation we will present structural and electronic information on monolayer films of metal, metal-oxide, and metal-carbides on diamond. The surface formation energies and electronic properties of diamond-metal surfaces Perder Burke Ernzerhof (PBE) exchange-correlation functional with a 6x6 monkhorst-Pack kpoint mesh and a plane wave cut off of 500eV. The optimized structure contained 42 atoms, allowing 14 layers of C to relax and reconstruct. In our study, we found that Mo (-0.652eV) and Zr (-0.857eV had a higher absorption potential energy compared to Al (0.180eV) and Ti (-0.220eV). The surface formation energy of four Zr atoms bound with four carbon atoms is -0.943eV. Additionally, for Zr when an oxygen atom is bridged across two metal atoms, in what is an ether configuration, it exhibits a highest formation energy for all metal- oxides. The surface formation energy indicates Zr and Mo has a greater strength attraction to a diamond (100) surface than Al and Ti.