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Transmission electron microscopy study of Pb-depleted disks in PbTe-based alloys

Published online by Cambridge University Press:  23 February 2011

Hengzhi Wang
Affiliation:
Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467
Qinyong Zhang
Affiliation:
Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467
Bo Yu
Affiliation:
Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467
Hui Wang
Affiliation:
Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467
Weishu Liu
Affiliation:
Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467
Gang Chen*
Affiliation:
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
Zhifeng Ren*
Affiliation:
Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467
*
a)Address all correspondence to these authors. e-mail: [email protected]
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Abstract

Even though the crystal structure of lead telluride (PbTe) has been extensively studied for many years, we discovered that the structure has a strong tendency to form Pb-depleted disks on {001} planes. These disks are around 2–5 nm in diameter and less than 0.5 nm in thickness, with a volume density of around 9 × 1017 cm−3, resulting in lattice strain fields (3–20 nm) on both sides of the disks along their normal directions. Moreover, such disks were also observed in Pb-rich Pb1.3Te, Pb-deficient PbTe1.3, and thallium (Tl)-doped Tl0.01Pb0.99Te and Tl0.02Pb0.98Te crystals. Because of the effects of diffraction contrast imaging by transmission electron microscopy and orientations of the crystals, these native lattice strain fields were incorrectly recognized as precipitates or nanoinclusions in PbTe-based materials. This discovery provides new insight into the formation mechanism of the precipitates or nanoinclusions in PbTe-based materials.

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Articles
Copyright
Copyright © Materials Research Society 2011

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