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Crystal and electronic structure of PbTe/CdTe nanostructures.

Bukała M, Sankowski P, Buczko R, Kacman P - Nanoscale Res Lett (2011)

Bottom Line: In this article, the authors reported a theoretical study of structural and electronic properties of PbTe inclusions in CdTe matrix as well as CdTe nano-clusters in PbTe matrix.The calculations show that both kinds of inclusions lead to changes of the DOS of the carriers near the Fermi level, which may affect optical, electrical and thermoelectric properties of the material.These changes depend on the size, shape, and concentration of inclusions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physics PAS, Al, Lotnikow 32/46, 02-668 Warsaw, Poland. bukala@ifpan.edu.pl.

ABSTRACT
In this article, the authors reported a theoretical study of structural and electronic properties of PbTe inclusions in CdTe matrix as well as CdTe nano-clusters in PbTe matrix. The structural properties are studied by ab initio methods. A tight-binding model is constructed to calculate the electron density of states (DOS) of the systems. In contrast to the ab initio methods, the latter allows studying nanostructures with diameters comparable to the real ones. The calculations show that both kinds of inclusions lead to changes of the DOS of the carriers near the Fermi level, which may affect optical, electrical and thermoelectric properties of the material. These changes depend on the size, shape, and concentration of inclusions.

No MeSH data available.


(Color online) Model of a CdTe A-QD embedded in a PbTe matrix. The blue, red, and grey balls denote Pb, Cd, and Te atoms, respectively. The whole rhombo-cubo-octahedral A-QD is shown in the inset.
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Figure 2: (Color online) Model of a CdTe A-QD embedded in a PbTe matrix. The blue, red, and grey balls denote Pb, Cd, and Te atoms, respectively. The whole rhombo-cubo-octahedral A-QD is shown in the inset.

Mentions: The model nano-objects are cut out from the bulk material: the NWs from PbTe, whereas A-NWs and A-QDs from CdTe. The considered nano-objects are then inserted into the matrix composed of the other material, assuming common Te sub-lattice. In the calculations, periodic boundary conditions are used. The interfaces between the NWs (A-NWs) and the matrix are of {110} and {001} type. The same two types of planes and the {111} planes form the interfaces of the A-QD. As shown already in Ref. [12], the energies of all these interfaces are comparable, and the shape of 3 D nano-objects, from Wulff construction, should be rhombo-cubo-octahedral (the shape of the cross section of the wires should be a regular octagon). Cross-sectional views of the exemplary supercells of the NW and A-NW considered, are presented in Figure 1. In Figure 2, model of CdTe A-QD embedded in PbTe matrix is shown. The sizes of the simple-cubic supercells vary with the diameter of the nano-objects and the distances between them, i.e. with the thickness of the material of the matrix, which separates the inclusions. Our NWs and A-NWs are directed along the [001] axis and have diameters ranging from 1.2 to 10 nm. The considered A-QDs have diameters up to 4 nm. The distances between these inclusions are ranging from 0.6 to 2.6 nm.


Crystal and electronic structure of PbTe/CdTe nanostructures.

Bukała M, Sankowski P, Buczko R, Kacman P - Nanoscale Res Lett (2011)

(Color online) Model of a CdTe A-QD embedded in a PbTe matrix. The blue, red, and grey balls denote Pb, Cd, and Te atoms, respectively. The whole rhombo-cubo-octahedral A-QD is shown in the inset.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211172&req=5

Figure 2: (Color online) Model of a CdTe A-QD embedded in a PbTe matrix. The blue, red, and grey balls denote Pb, Cd, and Te atoms, respectively. The whole rhombo-cubo-octahedral A-QD is shown in the inset.
Mentions: The model nano-objects are cut out from the bulk material: the NWs from PbTe, whereas A-NWs and A-QDs from CdTe. The considered nano-objects are then inserted into the matrix composed of the other material, assuming common Te sub-lattice. In the calculations, periodic boundary conditions are used. The interfaces between the NWs (A-NWs) and the matrix are of {110} and {001} type. The same two types of planes and the {111} planes form the interfaces of the A-QD. As shown already in Ref. [12], the energies of all these interfaces are comparable, and the shape of 3 D nano-objects, from Wulff construction, should be rhombo-cubo-octahedral (the shape of the cross section of the wires should be a regular octagon). Cross-sectional views of the exemplary supercells of the NW and A-NW considered, are presented in Figure 1. In Figure 2, model of CdTe A-QD embedded in PbTe matrix is shown. The sizes of the simple-cubic supercells vary with the diameter of the nano-objects and the distances between them, i.e. with the thickness of the material of the matrix, which separates the inclusions. Our NWs and A-NWs are directed along the [001] axis and have diameters ranging from 1.2 to 10 nm. The considered A-QDs have diameters up to 4 nm. The distances between these inclusions are ranging from 0.6 to 2.6 nm.

Bottom Line: In this article, the authors reported a theoretical study of structural and electronic properties of PbTe inclusions in CdTe matrix as well as CdTe nano-clusters in PbTe matrix.The calculations show that both kinds of inclusions lead to changes of the DOS of the carriers near the Fermi level, which may affect optical, electrical and thermoelectric properties of the material.These changes depend on the size, shape, and concentration of inclusions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physics PAS, Al, Lotnikow 32/46, 02-668 Warsaw, Poland. bukala@ifpan.edu.pl.

ABSTRACT
In this article, the authors reported a theoretical study of structural and electronic properties of PbTe inclusions in CdTe matrix as well as CdTe nano-clusters in PbTe matrix. The structural properties are studied by ab initio methods. A tight-binding model is constructed to calculate the electron density of states (DOS) of the systems. In contrast to the ab initio methods, the latter allows studying nanostructures with diameters comparable to the real ones. The calculations show that both kinds of inclusions lead to changes of the DOS of the carriers near the Fermi level, which may affect optical, electrical and thermoelectric properties of the material. These changes depend on the size, shape, and concentration of inclusions.

No MeSH data available.