Chemical transformation of Te into new ternary phase Pb sub(m)Cu sub(n)Te sub(m+n) nanorods and their surface atom diffusion and optical properties

• Published in: RSC advances Vol. 6; no. 56; pp. 50599 - 50608
• Main Authors: Wang, Qun, Su, Ziming, Lv, Mingda, Li, Jianhuan, Sun, Baoyu, Zhang, Guangjun
• Format: Journal Article
• Language: English
• Published: 01.05.2016
• Subjects: Diffusion; Energy gaps (solid state); Nanomaterials; Nanorods; Nucleation; Preserves; Ternary systems; Transformations
• ISSN: 2046-2069
• DOI: 10.1039/c6ra07779j

A new stable phase of ternary Pb sub(m)Cu sub(n)Te sub(m+n) with rough surface, including one-dimensional (1D) bamboo-like shaped and curved nanorods with short branches, was first synthesized using Te as a sacrificial template. The structure does not exist in the bulk Cu sub(2)Te-PbTe phase diagram. It is revealed that the optimal Pb super(2+)/Cu super(2+) chemical reactivity synergistic effect can preserve the initial shape of the Te nanorod parent template, which involves small volume changes and secondary nucleation phenomenon along the entire length of the nanorods. Furthermore, the diffusion of surface atoms and a surface pre-melting on the short branches of the nanorods were observed upon in situ electron-beam irradiation. The average Cu atom diffusion distance calculated (3 10 super(-11) m s super(-1)) is higher than the reported value (1.34 10 super(-12) m s super(-1)) in Cu sub(2)O at 373 K, which is attributed to the local high temperature created by the incident electron irradiation and large surface to volume ratio of the nanomaterials. In addition, the Pb sub(m)Cu sub(n)Te sub(m+n) nanorods exhibit well-defined and size-dependent optical band gaps (E sub(g)) in the near-IR region. We envision that the Te template strategy is general and robust and offers easy access to other new phase ternary PbTe-based nanomaterials via carefully balancing the chemical reactivity of the precursor.