Structural and Electronic Properties of 3x1 Si (Ge)-Terminated Diamond (100) Surfaces*

With an increasing demand for high-powered control electronics in harsh environments, discerning the electronic and physical properties of diamond surfaces are critical for device applications because of their superior electronic and thermal properties. These surfaces exhibit attractive surface dependent structural and electronic properties. Motivated by this, we perform a DFT study into clean and oxidized variants of the reconstructed Si (Ge)-terminated diamond (100) surfaces. Moreover, utilizing the nudged elastic band (NEB) approach, a reconstruction mechanism between Si (Ge)-terminated ketone and ether surfaces are predicted. Electronic properties reveal a phase transition from metallic to semiconducting properties from the clean surface to Ge- and Si-terminated regimes. When oxidized, Si- and Ge-terminates exhibited a return to metallic properties in the bridged-ether configurations but displayed an increased bandgap from the clean surface of approximately 80% and 73%, respectively in the ether configuration. Furthermore, novel Si- and Ge- tilted terminates revealed topological insulating properties and provide interesting device fabrication opportunities.