Abstract:In this work, scanning tunnelling microscopy (STM) and scanning tunnelling spectroscopy (STS) were applied to investigate the surface morphology and the surface electronic structure of plasma-treated (100)-oriented CVD diamond films. These films were hydrogenated using a conventional MWPE-CVD (microwave plasma enhanced chemical vapour deposition) reactor containing a H2 or a H2/O2 mixture. A comparison is made between (100)-oriented CVD diamond films hydrogenated with and without a small addition of oxygen (1%… Show more
“…Therefore, that electron can transfer from the localized states below the Fermi level to up the top of valence band surface states, which may induce hopping surface conduction. This result is consistent with the very recent experiment that the oxygen-induced surface gap states may contribute to the SC for the hydrogenation surface processed by H 2 /O 2 mixture; namely, the surface states of OT structure may cause hopping surface conduction. 2 Differential charge density maps for (100) layer in the surface and adatoms, such as (a) C(100) (2 × 1):1H, (b) OT, (c) BR, and (d) C(100) (2 × 1):1OH. 3 TDOS of (a) clean C(100) (2 × 1), (b) C(100) (2 × 1):1H, (c) OT, (d) BR, and (e) C(100) (2 × 1):1OH.…”
Section: Resultssupporting
confidence: 93%
“…Diamond surfaces exhibit outstanding electronic properties such as negative electron affinity (NEA) and unique p-type surface conductivity (SC) in the case of hydrogen-terminated surfaces. , Structures and electronic properties of hydrogen-terminated diamond surfaces have been widely studied in both experiment and theory in past years. − However, recent experiments show that even brief exposure of hydrogenated diamonds to air results in gradual deterioration or disappearance of the SC, which is ascribed to oxygen. ,, A very recent experiment also indicated that oxygen has an important influence on the SC and/or on the presence of the surface state . It is well-known that molecular oxygen shows no appreciable sticking probability on diamond in vacuum, but a moist atmosphere may cause a slow oxidation of the surface under normal conditions.…”
The structural and electronic properties of diamond (100) surface, with hydrogen and oxygen terminations,
have been studied using density functional theory. The energy calculations indicate that a hydroxyl is the
most stable structure on the oxygenation surface. The surface properties with different terminations have
been investigated by means of density of states, charges, bond population, and differential charge density
maps. A novel explanation is proposed for the deterioration or disappearance of p-type surface conductivity
of diamond with surface oxygenation from the view of electron transfer. The results not only support that
hydrogen is a prerequisite factor for surface conductivity, but also explain very recent experimental observations.
“…Therefore, that electron can transfer from the localized states below the Fermi level to up the top of valence band surface states, which may induce hopping surface conduction. This result is consistent with the very recent experiment that the oxygen-induced surface gap states may contribute to the SC for the hydrogenation surface processed by H 2 /O 2 mixture; namely, the surface states of OT structure may cause hopping surface conduction. 2 Differential charge density maps for (100) layer in the surface and adatoms, such as (a) C(100) (2 × 1):1H, (b) OT, (c) BR, and (d) C(100) (2 × 1):1OH. 3 TDOS of (a) clean C(100) (2 × 1), (b) C(100) (2 × 1):1H, (c) OT, (d) BR, and (e) C(100) (2 × 1):1OH.…”
Section: Resultssupporting
confidence: 93%
“…Diamond surfaces exhibit outstanding electronic properties such as negative electron affinity (NEA) and unique p-type surface conductivity (SC) in the case of hydrogen-terminated surfaces. , Structures and electronic properties of hydrogen-terminated diamond surfaces have been widely studied in both experiment and theory in past years. − However, recent experiments show that even brief exposure of hydrogenated diamonds to air results in gradual deterioration or disappearance of the SC, which is ascribed to oxygen. ,, A very recent experiment also indicated that oxygen has an important influence on the SC and/or on the presence of the surface state . It is well-known that molecular oxygen shows no appreciable sticking probability on diamond in vacuum, but a moist atmosphere may cause a slow oxidation of the surface under normal conditions.…”
The structural and electronic properties of diamond (100) surface, with hydrogen and oxygen terminations,
have been studied using density functional theory. The energy calculations indicate that a hydroxyl is the
most stable structure on the oxygenation surface. The surface properties with different terminations have
been investigated by means of density of states, charges, bond population, and differential charge density
maps. A novel explanation is proposed for the deterioration or disappearance of p-type surface conductivity
of diamond with surface oxygenation from the view of electron transfer. The results not only support that
hydrogen is a prerequisite factor for surface conductivity, but also explain very recent experimental observations.
“…Such a treatment forms the oxygenterminated diamond surface and should, in accordance with literature data (e.g. [7][8][9][10]), suppress the surface conductivity. Nevertheless, somewhat astonishingly, the measured currents in the treated samples, in comparison with 'as-delivered' samples, increased up to two orders of magnitude (see details below).…”
Using point-contact configuration, the ohmic and nonlinear space-charge-limited electronic transport in semi-insulating single-crystalline diamond was studied. Analysis of I-V curves enabled us to determine the bulk resistivity and concentration of electrically active traps, i.e. parameters crucial for potential applications of this material. It has been further shown that the charge carrier injection into the bulk diamond is strongly influenced by the surface treatment in oxygen plasma changing its surface conductivity. The observed behaviour has been accounted for within the frame of semi-quantitative simple model.
“…Differences in surface structure and roughness may result in varying contact properties, and thus, different detector operation at positive and negative bias. Systematic contact studies have been performed by other groups [28,29]. In our own experiments, we found the clear trend that the surface treatment of the crystals is more crucial for the final detector performance than the choice of the contact metal used as electrode.…”
Section: Physical Parameters Of the Samplesmentioning
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