Journal of Materials Research

Articles

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

Hengzhi Wanga1, Qinyong Zhanga1, Bo Yua1, Hui Wanga1, Weishu Liua1, Gang Chena2 c1 and Zhifeng Rena3 c2

a1 Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467

a2 Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139

a3 Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467

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.

(Received September 30 2010)

(Accepted December 08 2010)

Key Words:

  • Pb;
  • Te;
  • Transmission electron microscopy

Correspondence:

c1 Address all correspondence to these authors. e-mail: gchen2@mit.edu

c2 e-mail: renzh@bc.edu

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