Utilizing density functional theory (DFT), we report a comparative study of the surface-dependent structural and electronic properties for hydrogenated and group-IV terminated (111) diamond surfaces in the bulk-like and reconstructed structural phases. The non-oxidized and oxidized variants are studied to further our understanding of experimentally proposed structures and expand the library of chemically relevant terminations for ultra-wide bandgap (UWBG) materials. Our analysis reveals, when oxidized, the formation of an epoxy-like SiO(GeO), a Si2O(Ge2O) adlayer, and a peroxide-bridged Si2O2(Ge2O2) layer on the diamond surface are favorable. Hydrogenated and epoxy oxidized Pandey chain surfaces resulted in gapped systems of 2.65 eV and 3.02 eV, respectively. We report a surface formation energy difference of -0.04 eV for the oxidized epoxy system compared to the hydrogenated. Additionally, epoxy-like and ketone configurations exhibit negative electron affinities (NEA) and semiconducting gaps, while Si(Ge) adlayers and peroxide-bridged structures possess metallic properties. Our findings establish a structure-property relationship of various non-oxidized and oxidized group-IV terminations for the (111) surface that may prove useful in high-power, high-frequency device design.

DFT investigation of hydrogenated and oxidized group-IV terminated (111) diamond surfaces

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.