ELECTRON MICROSCOPIC STUDIES OF CuS NANOCRYSTALS FORMED IN LANGMUIR — BLODGETT FILMS
A. K. Gutakovskii1,2, L. L. Sveshnikova1, S. A. Batsanov1, N. A. Eryukov1
1Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent’eva 13, Novosibirsk, 630090 Russia
2Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090 Russia
Keywords: Langmuir — Blodgett, high-resolution electron microscopy, energy dispersive X-ray analysis, crystal structure, copper sulfide nanocrystals
Abstract
The morphology and structure of CuS crystals formed during sulfidation of copper behenate films obtained by the Langmuir — Blodgett (LB) method have been studied using high resolution electron microscopy. The average size of these crystals is about 3 nm and increases by a factor of approximately 2.2 after annealing at a temperature of 150 ºC or above. Analysis of interplanar distances has shown that in the range of annealing temperatures of 150–200 ºC, CuS nanocrystals have a P63/mmc hexagonal crystal lattice with parameters a = 0.38 nm and c = 1.64 nm. At annealing temperatures of 250 ºC or above, the Cu2S crystalline phase begins to form, in addition to CuS nanocrystals. The proportion of this phase increases with increasing annealing temperature. Cu2S nanocrystals have a hexagonal crystal lattice type with the P63/mmc spatial group and unit cell parameters a = 0.39 nm and c = 0.68 nm. Quantitative evaluation of copper and sulfur in individual CuS and Cu2S nanocrystals was performed by local analysis of characteristic X-ray spectra.
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