Geometries and electronic structures of the hydrogenated diamond (100) surface upon exposure to active ions: A first principles study

Abstract

To elucidate the effects of physisorbed active ions on the geometries and electronic structures of hydrogenated diamond films, models of HCO − 3 , H 3 O + , and OH − ions physisorbed on hydrogenated diamond (100) surfaces were constructed. Density functional theory was used to calculate the geometries, adsorption energies, and partial density of states. The results showed that the geometries of the hydrogenated diamond (100) surfaces all changed to different degrees after ion adsorption. Among them, the H 3 O + ion affected the geometry of the hydrogenated diamond (100) surfaces the most. This is well consistent with the results of the calculated adsorption energies, which indicated that a strong electrostatic attraction occurs between the hydrogenated diamond (100) surface and H 3 O + ions. In addition, electrons transfer significantly from the hydrogenated diamond (100) surface to the adsorbed H 3 O + ion, which induces a downward shift in the HOMO and LUMO energy levels of the H 3 O + ion. However, for active ions like OH − and HCO − 3 , no dramatic change appears for the electronic structures of the adsorbed ions.

A first‐principles investigation on interactions between various surface‐terminated diamond films

“…However, for the diamond surfaces terminated with OH and NH 2 radicals, no obvious interaction between diamond surfaces is observed because the C─C bond lengths stay the same as those without an interface. In addition, the C─H bond length without an interface is 1.09 Å, keeping well with 1.10 Å reported by Kern et al and our previous studies . The C─F bond length here is 1.37 Å, 0.28 Å longer than C─H bond length.…”

“…In addition, the C─H bond length without an interface is 1.09 Å, keeping well with 1.10 Å reported by Kern et al 35 and our previous studies. 28,36 The C─F bond length here is 1.37 Å, 0.28 Å longer than C─H bond length. It is very similar to the results obtained by Wang et al by using the first principles method.…”

“…Thus, from the aspects of computational efficiency and accuracy, the slab thickness of the surface-terminated diamond surface model includes eight carbon atom layers (also eight C atoms in each layer) and two termination layers. In the previous computational studies, eight layers 21,27 even six layers 22,28 of carbon atoms were also proved thick enough to represent the diamond surfaces. For the H-terminated diamond (100) surface, the reconstructed 2 × 1 structure is also the most stable structure, the same as that of the clean surface.…”

Interactions between hydrogenated diamond surface and adsorbates with different concentration of NO2 molecules: A first‐principles study

“…After adsorbed with NO 2 or NO 2 + H 2 O, their band structures are similar, which indicates no density of states corresponding to the interaction between the adsorbates and oxygenated diamond surface near VBM level. The results are quite consistent with the previous reports …”

“…At the same time, hydrogen atoms in the subsurface region of diamond films would generate deep surface states, which are also impossible to lead to high surface conductivity . Afterwards, it is deduced that hydrogen termination is necessary but not sufficient for high surface conductivity of diamond films, while surface adsorbed water layer is necessary . Hydrogenated diamond film and the adsorbed water layer construct a tiny electrochemical system.…”