Total-energy calculations of semiconductor surface reconstructions

LaFemina, John P.

doi:10.1016/0167-5729(92)90014-3

Cited by 171 publications

(31 citation statements)

References 531 publications

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“…Defining Dq = q slab À q bulk and Db = b slab À b bulk as the difference between the slab and bulk atomic charges and overlap populations, respectively, one can conclude from the computed Dq and Db values that the upper surface layers are characterized by a significant decrease of ionicity compared to the bulk system, and these differences attenuate from the surface to the innermost layers of the slab. This is in line with the previously described phenomena that the surface redistributes the occupied anion-derived dangling bond charge density into bonding orbitals upon relaxation, 68 which is reflected by the computed band structure reported in Fig. 6.…”

Section: Cdse Wurtzite 10à10 Surfacesupporting

confidence: 92%

Investigation of the bulk and surface properties of CdSe: insights from theory

Szemjonov

Pauporté

Ciofini

et al. 2014

Phys. Chem. Chem. Phys.

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CdSe, in the form of quantum dots, is a semiconductor material extensively used for photovoltaic applications. We have performed a comprehensive density functional theory investigation of the geometrical and electronic properties of CdSe bulk crystals (for both the wurtzite and zinc blende phases) as well as their wurtzite (10-10) surface. Several combinations of Gaussian-type orbital basis sets and exchange-correlation functionals have been tested with a periodic formalism. The computational method for further studies was selected on the basis of the comparison of computed geometrical and electronic properties to available experimental data for the bulk crystals of CdSe, as well as to additional projector-augmented wave calculations. In a second step, the so-defined protocol was used to successfully simulate CdSe wurtzite nanocrystals exposing their nonpolar (10-10) surface. Most importantly, we have shown that the presented computational protocol is accurate to model not only bulk crystals but also surfaces, thus providing a powerful theoretical tool to simulate the light harvesting components of quantum dot sensitized solar cells.

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Section: Cdse Wurtzite 10à10 Surfacesupporting

confidence: 92%

Investigation of the bulk and surface properties of CdSe: insights from theory

Szemjonov

Pauporté

Ciofini

et al. 2014

Phys. Chem. Chem. Phys.

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“…A similar sort of charge transfer mechanism has also been suggested to occur within the buckled dimers on the Si(100)-2 × 1 surface, to a smaller extent. [23][24][25][26] This is the reason why the rest atom peak of 2 × 2 lies below the E F , while the adatom peak is above it. To reiterate, it is because of the 1:1 ratio of adatoms to rest atoms in the 2 × 2 supercell that this system ends up with a semiconducting electronic structure.…”

Section: B Comparison Of Reconstructionsmentioning

confidence: 99%

Electronic properties of Si(111)-7×7and related reconstructions: Density functional theory calculations

Smeu

Guo

et al. 2012

Phys. Rev. B

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The 7 × 7 reconstruction of Si(111) has the interesting property of being metallic despite bulk Si being a semiconductor. This surface has a complex reconstruction that takes on a dimer-adatom stacking fault (DAS) structure composed of adatoms, rest atoms, and several other key features. It is believed that the dangling bonds of the adatoms play a crucial role in the high conductivity and that this is predominantly a surface-state band effect. To elucidate the details of this mechanism, we investigate a set of related Si(111) reconstructions of increasing complexity in order to resolve the effect of the different DAS features on the electronic and transport properties of the Si(111)-7 × 7 surface. Density functional theory calculations are carried out on the √ 3 × √ 3-R30 • , 2 × 2, 5 × 5, and 7 × 7 reconstructions of Si(111). Since these surfaces are modeled as two-dimensional slabs, a careful investigation is carried out to determine the slab thickness needed to capture the structural and electronic properties of these systems. The densities of states (DOSs) projected on different atoms in these surfaces are then compared, revealing that the √ 3 × √ 3, 5 × 5, and 7 × 7 surfaces are metallic, while the 2 × 2 surface is semiconducting. Finally, the DOSs for Si(111)-7 × 7 are related to scanning tunneling microscope data to offer an explanation for different adatom prominence trends depending on Si sample doping.

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“…One could envision even more sophisticated treatments which account for the different size of surface atoms compared to bulk atoms, surface relaxations, etc. However, based on the data for the bulk surfaces [20] these should be much smaller corrections (l/lOO's of nm). Furthermore while theoretical calculations based on continuum solid state concepts assume a step function in the potential at the surface, they do not in fact define where that step occurs in terms of atorin spacings.…”

Section: 2lc Hrtem Sizingmentioning

confidence: 99%

“…This is a universal feature of this surface' for binary tetrahedral semiconductors. [20] It only involves a small bond-length conserving rotation which does not significantly change the surface connectivity or planarity. Its main effect is to shift electron density from the cationic atoms, Cd in this case, to the anionic species, Se here.…”

Section: Nanocrystal Morphologymentioning

confidence: 99%

See 1 more Smart Citation

The structure and morphology of semiconductor nanocrystals

Kadavanich

1997

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Total-energy calculations of semiconductor surface reconstructions

Cited by 171 publications

References 531 publications

Investigation of the bulk and surface properties of CdSe: insights from theory

Investigation of the bulk and surface properties of CdSe: insights from theory

Electronic properties of Si(111)-7×7and related reconstructions: Density functional theory calculations

The structure and morphology of semiconductor nanocrystals

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