Ground-state structure of oxidized diamond (100) surface: An electronically nearly surface-free reconstruction

Structural, Electronic, and Mechanical Properties of 2D Oxidized Diamond (100) Nanofilms

“…Meantime, the bond lengths between surface O atom and neighboring C atom ( d 2 ) are 1.196–1.197 and 1.197–1.198 Å, respectively, suggesting that the C═O double bonds are formed. [ 28 ] The lengths of interior C─C bond of the nanofilms structures are 1.523–1.551 Å, being similar with those in bulk diamond. [ 32 ] Therefore, the interior of 2D diamond (100) nanofilms maintain the bulk diamond phase after surface oxygenation and hydrogenation.…”

“…[ 32,35,36 ] On the other hand, the methoxyacetone model surface contains both carbonyl and epoxide groups as the dominant structure, this model is predicted to be stable with a lower formation energy determined by a global surface structure search method. [ 28 ] As shown in Figure , four kinds of oxidized structures are built, both surfaces are oxidized with ether model (named as EE‐DNFs), one side is oxidized with ether model and another side is hydrogenated (named as EH‐DNFs), both surfaces are oxidized based on methoxyacetone model (named as MM‐DNFs), one side is oxidized based on methoxyacetone model and another side is hydrogenated (named as MH‐DNFs). The layer number n of DNFs is defined as number of C atomic layer across the nanofilms, as labeled in Figure 1.…”

“…For EE‐DNFs and EH‐DNFs, the most of bond lengths between the nearest neighboring C and O atoms on surface ( d 1 ) are 1.505–1.506 Å, being similar with previous theoretical results. [ 28,36–38 ] For the case of MM‐DNFs and MH‐DNFs structures, the majority bond lengths between O atom in the second layer and the nearest C atom ( d 1 ) are 1.450–1.451 and 1.452–1.453 Å, respectively. It confirms the formation of C─O single bond on diamond nanofilms surface.…”

“…It is found that the band structures characteristics are evidently different from those for pristine, [ 24 ] hydrogenated and fluorinated diamond (100) nanofilms, [ 26 ] and oxidized bulk diamond (100) surface. [ 28 ] The EE‐DNFs and EH‐DNFs at n = 6 show the direct bandgap semiconductor characteristic with both conductance band minimum (CBM) and valence band maximum (VBM) being at Γ point. E g values are 1.308 and 1.856 eV, respectively.…”

“…[ 23,25–27 ] Noted that the surface termination is necessary for stabilizing the diamond phase. [ 15–17,19,20,28 ] In addition to H termination for bulk diamond surface, the oxygen (O) termination is the general surface treatment method. [ 1 ] However, H would desorb from the bulk diamond surface with H termination at elevated temperature.…”