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Interactions between hydrogenated diamond surface and adsorbates with different concentration of NO 2 molecules: A first‐principles study
Author(s) -
Liu Fengbin,
Chen Wenbin,
Cui Yan,
Jiao Zhiwei,
Qu Min,
Cao Leigang
Publication year - 2018
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.6514
Subject(s) - diamond , molecule , adsorption , chemistry , mulliken population analysis , surface conductivity , density functional theory , conductivity , chemical physics , density of states , crystallography , materials science , computational chemistry , organic chemistry , physics , condensed matter physics
To elucidate the effects of NO 2 and H 2 O molecules on the surface conductivity of hydrogenated diamond film, models of various adsorbates containing different molecular ratio of NO 2 and H 2 O on hydrogenated diamond (100) surfaces were constructed. The adsorption energies, equilibrium geometries of adsorbates, density of states, and atomic Mulliken populations were studied by using first‐principles method. The results showed that H 2 O molecule in the adsorbate could weaken the interactions between the adsorbates and hydrogenated diamond surface significantly. Compared with H 2 O molecule, NO 2 molecule relaxes more dramatically when adsorbed on hydrogenated diamond surface. In addition, density of states for C(100):H–2NO 2 , C(100):H–NO 2 , and C(100):H–NO 2 + H 2 O systems are very similar to each other, which indicates an obvious peak at valence band maximum level for all the three samples. It can be attributed to mainly single occupied molecule orbital of NO 2 molecule and slightly C–H bond of C(100):H substrate. When the adsorbates contain one NO 2 and two H 2 O molecules, the peak shifts slightly into valence band, but its intensity increases significantly. All the samples exhibit p ‐type surface conductivity when adsorbed with pure NO 2 molecules, and the surface conductivity remains as H 2 O molecules added into the NO 2 adsorbate layer. However, for oxygenated diamond surface, very week interactions generate between diamond surface and various adsorbates. All the oxygenated diamond (100) surfaces with various adsorbates containing different NO 2 and H 2 O molecules on it exhibit an insulating property.