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Structural properties and variable-range hopping conductivity of Cu2SnS3


Hong T T Nguyen, V S Zakhvalinskii , Thao T Pham, N T Dang, Tuan V Vu, E A Pilyuk and G V Rodriguez

Source title: 
Materials Research Express, 6: 055915, 2019 (ISI)
Academic year of acceptance: 

In the present work, we investigated the elemental composition, structural and electrical properties of Cu2SnS3 (CTS) ternary semiconductor synthesized by the pyrolytic decomposition of the precursors in vacuum. The molar ratio of Sn/Cu in the precursor solution was varied from 0.2 to 0.6. The x-ray diffraction and Raman analyses confirmed that the synthesized samples mainly consist of tetragonal CTS phase with space group $I\overline{4}2m.$ The dependence of the conductivity of CTS samples on temperature was investigated in the temperature range 10-300 K. A crossover between nearest-neighbor hopping and Mott variable-range hopping conduction mechanisms were observed at $T\approx 145\,{\rm{K}}.$ Analysis of the data yielded the values of the relative acceptor concentration $N/{N}_{\unicode{x00421}}\approx 0.77-0.85$ with the critical concentration of the metal–insulator transition (MIT) ${N}_{\unicode{x00421}}\approx 6.9\times {10}^{17}$ cm−3, the localization radius $a/{a}_{B}\approx 4.4-6.7$ with the Bohr radius ${a}_{B}\approx 21.1\,{\rm{\mathring{\rm{A}} }},$ the dielectric permittivity far from the MIT κ0 = 10.7, the mean acceptor energy ${E}_{0}\approx 42$ meV and the mean density of the localized states $g\approx \left(1.7-6.5\right)\times {10}^{16}$ meV−1cm−3.