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One-step synthesis of PbSe-ZnSe composite thin film.

Abe S - Nanoscale Res Lett (2011)

Bottom Line: The XRD result reveals that the solubility limit of Pb in ZnSe is quite narrow, less than 1 mol%, with obvious phase-separation in the composite thin films.A nanoscale elemental mapping of the film containing 5 mol% PbSe indicates that isolated PbSe nanocrystals are dispersed in the ZnSe matrix.The use of a phase-separating PbSe-ZnSe system and HWD techniques enables simple production of the composite package.

View Article: PubMed Central - HTML - PubMed

Affiliation: Research Institute for Electric and Magnetic Materials, Sendai 982-0807, Japan. abe@denjiken.ne.jp.

ABSTRACT
This study investigates the preparation of PbSe-ZnSe composite thin films by simultaneous hot-wall deposition (HWD) from multiple resources. The XRD result reveals that the solubility limit of Pb in ZnSe is quite narrow, less than 1 mol%, with obvious phase-separation in the composite thin films. A nanoscale elemental mapping of the film containing 5 mol% PbSe indicates that isolated PbSe nanocrystals are dispersed in the ZnSe matrix. The optical absorption edge of the composite thin films shifts toward the low-photon-energy region as the PbSe content increases. The use of a phase-separating PbSe-ZnSe system and HWD techniques enables simple production of the composite package.

No MeSH data available.


XRD pattern of powder-synthesized Zn1-xPbxSe with respect to x. Dots indicate PbSe and circles indicate ZnSe.
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Figure 2: XRD pattern of powder-synthesized Zn1-xPbxSe with respect to x. Dots indicate PbSe and circles indicate ZnSe.

Mentions: The bulk PbSe-ZnSe phase diagram is now revealed at ZnSe concentrations below 45 at.% (Pb-rich side) [12], although the phase diagram of the Zn-rich side still remains unclear. Powder synthesis of a PbSe-ZnSe system was investigated prior to investigating the film preparation. Figure 2 depicts the powder XRD pattern of the Zn1-xPbxSe system. In the powder synthesis, the bulk PbSe and ZnSe thus synthesized was used as starting materials. The desired composition of the system was prepared in an agate mortar and vacuum-sealed in a quartz tube for heat treatment at 1273 K for 48 h. Finally, the samples were successively water-quenched to maintain the solubility range at a synthesis temperature then crushed into powder for the following experiment setup. At x = 0, all of the XRD peaks are assigned to the zinc-blend structure of ZnSe, with a lattice constant of 0.5669 nm, estimated from the XRD peaks in a high-2θ range from 100° to 155°, using the Nelson-Riley function [19]. The XRD peak of PbSe with an NaCl structure appears at Pb concentrations exceeding 0.02. The lattice constant of the ZnSe at x = 0.02 is the same as at x = 0, within the precision of the experiment technique. This result indicates that the solubility range of Pb in ZnSe is negligible. In contrast, the lattice constant of PbSe is estimated to be 0.6121 nm at x = 1.0 and 0.6117 nm at x = 0.98. A slight decrease in the lattice constant is seen in PbSe, due to the difference in ionic radii of Pb and Zn. Weak XRD peaks of ZnSe are also observed at x = 0.98 as seen in the inset for easier viewing. This result indicates that the solubility range of Zn in PbSe is less than 0.02 at 1273 K. The result is in good agreement with the previous result [12]. The phase separation of the PbSe-ZnSe system is thus also seen on the Zn-rich side in the thermal-equilibrium state. The film preparation for PbSe-ZnSe composite is next investigated based on these results.


One-step synthesis of PbSe-ZnSe composite thin film.

Abe S - Nanoscale Res Lett (2011)

XRD pattern of powder-synthesized Zn1-xPbxSe with respect to x. Dots indicate PbSe and circles indicate ZnSe.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211412&req=5

Figure 2: XRD pattern of powder-synthesized Zn1-xPbxSe with respect to x. Dots indicate PbSe and circles indicate ZnSe.
Mentions: The bulk PbSe-ZnSe phase diagram is now revealed at ZnSe concentrations below 45 at.% (Pb-rich side) [12], although the phase diagram of the Zn-rich side still remains unclear. Powder synthesis of a PbSe-ZnSe system was investigated prior to investigating the film preparation. Figure 2 depicts the powder XRD pattern of the Zn1-xPbxSe system. In the powder synthesis, the bulk PbSe and ZnSe thus synthesized was used as starting materials. The desired composition of the system was prepared in an agate mortar and vacuum-sealed in a quartz tube for heat treatment at 1273 K for 48 h. Finally, the samples were successively water-quenched to maintain the solubility range at a synthesis temperature then crushed into powder for the following experiment setup. At x = 0, all of the XRD peaks are assigned to the zinc-blend structure of ZnSe, with a lattice constant of 0.5669 nm, estimated from the XRD peaks in a high-2θ range from 100° to 155°, using the Nelson-Riley function [19]. The XRD peak of PbSe with an NaCl structure appears at Pb concentrations exceeding 0.02. The lattice constant of the ZnSe at x = 0.02 is the same as at x = 0, within the precision of the experiment technique. This result indicates that the solubility range of Pb in ZnSe is negligible. In contrast, the lattice constant of PbSe is estimated to be 0.6121 nm at x = 1.0 and 0.6117 nm at x = 0.98. A slight decrease in the lattice constant is seen in PbSe, due to the difference in ionic radii of Pb and Zn. Weak XRD peaks of ZnSe are also observed at x = 0.98 as seen in the inset for easier viewing. This result indicates that the solubility range of Zn in PbSe is less than 0.02 at 1273 K. The result is in good agreement with the previous result [12]. The phase separation of the PbSe-ZnSe system is thus also seen on the Zn-rich side in the thermal-equilibrium state. The film preparation for PbSe-ZnSe composite is next investigated based on these results.

Bottom Line: The XRD result reveals that the solubility limit of Pb in ZnSe is quite narrow, less than 1 mol%, with obvious phase-separation in the composite thin films.A nanoscale elemental mapping of the film containing 5 mol% PbSe indicates that isolated PbSe nanocrystals are dispersed in the ZnSe matrix.The use of a phase-separating PbSe-ZnSe system and HWD techniques enables simple production of the composite package.

View Article: PubMed Central - HTML - PubMed

Affiliation: Research Institute for Electric and Magnetic Materials, Sendai 982-0807, Japan. abe@denjiken.ne.jp.

ABSTRACT
This study investigates the preparation of PbSe-ZnSe composite thin films by simultaneous hot-wall deposition (HWD) from multiple resources. The XRD result reveals that the solubility limit of Pb in ZnSe is quite narrow, less than 1 mol%, with obvious phase-separation in the composite thin films. A nanoscale elemental mapping of the film containing 5 mol% PbSe indicates that isolated PbSe nanocrystals are dispersed in the ZnSe matrix. The optical absorption edge of the composite thin films shifts toward the low-photon-energy region as the PbSe content increases. The use of a phase-separating PbSe-ZnSe system and HWD techniques enables simple production of the composite package.

No MeSH data available.