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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) The DOS near the Fermi level for PbTe matrix with CdTe A-QDs. The diameters of the A-QDs are 2 nm (black line) and 3.5 nm (dashed green line). The distance between the A-QDs is always the same, 1.2 nm.
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Figure 7: (Color online) The DOS near the Fermi level for PbTe matrix with CdTe A-QDs. The diameters of the A-QDs are 2 nm (black line) and 3.5 nm (dashed green line). The distance between the A-QDs is always the same, 1.2 nm.

Mentions: Next, ZB CdTe A-NWs and A-QDs embedded in RS PbTe matrix are described. It can be recalled that in contrast to the NWs, in the anti-structures, the carriers are located in the PbTe channels between inclusions and can move in any direction. Thus, the low-dimensional sub-bands in the DOS are not to be expected. Still, how the DOS changes with the diameter of the anti-objects and the thickness of the PbTe matrix between the inclusion walls is studied. At first, the distance between the model A-NWs is changed while their diameter is kept constant. The results are presented in Figure 5. One notes that the thicker the PbTe channels between A-NWs, the less the DOS differs from that of PbTe bulk material. Diminishing the distance between the A-NWs leads to an increase of the DOS derivative at the Fermi level for both kinds of carriers. In Figure 6, the results for different diameters of A-NWs separated by the same distance are presented. The resonances in the DOS, which can be seen in the figure, result most probably from the confinement in the PbTe material in-between CdTe A-NWs. These PbTe channels can be considered as interconnected NWs. In Figure 7, similar results obtained for A-QDs, with diameters 2 and 3.5 nm, are shown. In the case of A-QDs, there is much more PbTe material in-between the inclusions, as compared to the A-NWs, and here the resonances are less pronounced and appear for higher energies.


Crystal and electronic structure of PbTe/CdTe nanostructures.

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

(Color online) The DOS near the Fermi level for PbTe matrix with CdTe A-QDs. The diameters of the A-QDs are 2 nm (black line) and 3.5 nm (dashed green line). The distance between the A-QDs is always the same, 1.2 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 7: (Color online) The DOS near the Fermi level for PbTe matrix with CdTe A-QDs. The diameters of the A-QDs are 2 nm (black line) and 3.5 nm (dashed green line). The distance between the A-QDs is always the same, 1.2 nm.
Mentions: Next, ZB CdTe A-NWs and A-QDs embedded in RS PbTe matrix are described. It can be recalled that in contrast to the NWs, in the anti-structures, the carriers are located in the PbTe channels between inclusions and can move in any direction. Thus, the low-dimensional sub-bands in the DOS are not to be expected. Still, how the DOS changes with the diameter of the anti-objects and the thickness of the PbTe matrix between the inclusion walls is studied. At first, the distance between the model A-NWs is changed while their diameter is kept constant. The results are presented in Figure 5. One notes that the thicker the PbTe channels between A-NWs, the less the DOS differs from that of PbTe bulk material. Diminishing the distance between the A-NWs leads to an increase of the DOS derivative at the Fermi level for both kinds of carriers. In Figure 6, the results for different diameters of A-NWs separated by the same distance are presented. The resonances in the DOS, which can be seen in the figure, result most probably from the confinement in the PbTe material in-between CdTe A-NWs. These PbTe channels can be considered as interconnected NWs. In Figure 7, similar results obtained for A-QDs, with diameters 2 and 3.5 nm, are shown. In the case of A-QDs, there is much more PbTe material in-between the inclusions, as compared to the A-NWs, and here the resonances are less pronounced and appear for higher energies.

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.