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Tunable PbTe nanocolloids and nanolayers: HTSP precipitation, spectral properties and light-hole band lowering due to quantization

A. TODOSICIUC1,* , A. NICORICI1, T. GUTSUL1, F. GRAMM2, L. BRAGINSKY3, V. SHKLOVER3

Affiliation

  1. Institute of Electronic Engineering and Nanotechnologies AS, Academiei str. 3/3, Chisinau 2028, Moldova
  2. EMEZ – Electron Microscopy ETH Zürich, Wolfgang Pauli Strasse 16, 8093 Zurich, Switzerland,
  3. Laboratory of Crystallography, Department of Materials, ETH Zürich, Wolfgang Pauli Strasse 10, 8093 Zürich, Switzerland

Abstract

Colloidal suspensions of PbTe nanoparticles coated with oleic acid (OA) were obtained using a high-temperature solution phase (HTSP) method. Both diphenyl ether and squalane were used as high-boiling heat-transfer agents. It was shown that the change in standard synthesis conditions, such as the temperature of reaction and the group IV/group VI precursor molar ratio, led to precipitation of the nanocrystalline tellurium in parallel with PbTe nanoparticles. Bonding between the oleic acid and nanoparticles (NP) was investigated using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results indicated that oleic acid coordinated the nanoparticles symmetrically through carboxyl groups, and the interaction modes were bridging bidentate and chelating interactions. The strong coordination by the capping monolayer made the NP stable against oxidation. In contrast to bulk, nanocrystalline PbTe possesses photosensitivity to IR radiation at low temperatures enabling electrical conductivity, which itself has an activation character with rising temperature..

Keywords

Lead telluride nanocrystals, HTSP synthesis, Colloidal solutions.

Submitted at: June 11, 2010
Accepted at: Aug. 12, 2010

Citation

A. TODOSICIUC, A. NICORICI, T. GUTSUL, F. GRAMM, L. BRAGINSKY, V. SHKLOVER, Tunable PbTe nanocolloids and nanolayers: HTSP precipitation, spectral properties and light-hole band lowering due to quantization, Journal of Optoelectronics and Advanced Materials Vol. 12, Iss. 8, pp. 1720-1728 (2010)