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Ternary SnS(2-x)Se(x) Alloys Nanosheets and Nanosheet Assemblies with Tunable Chemical Compositions and Band Gaps for Photodetector Applications.

Yu J, Xu CY, Li Y, Zhou F, Chen XS, Hu PA, Zhen L - Sci Rep (2015)

Bottom Line: The variation tendency of band gap was also confirmed by first-principles calculations.The photoelectrochemical measurements indicate that the performance of ternary SnS(2-x)Se(x) alloys depends on their band structures and morphology characteristics.Furthermore, SnS(2-x)Se(x) photodetectors present high photoresponsivity with a maximum of 35 mA W(-1) and good light stability in a wide range of spectral response from ultraviolet to visible light, which renders them promising candidates for a variety of optoelectronic applications.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.

ABSTRACT
Ternary metal dichalcogenides alloys exhibit compositionally tunable optical properties and electronic structure, and therefore, band gap engineering by controllable doping would provide a powerful approach to promote their physical and chemical properties. Herein we obtained ternary SnS(2-x)Se(x) alloys with tunable chemical compositions and optical properties via a simple one-step solvothermal process. Raman scattering and UV-vis-NIR absorption spectra reveal the composition-related optical features, and the band gaps can be discretely modulated from 2.23 to 1.29 eV with the increase of Se content. The variation tendency of band gap was also confirmed by first-principles calculations. The change of composition results in the difference of crystal structure as well as morphology for SnS(2-x)Se(x) solid solution, namely, nanosheets assemblies or nanosheet. The photoelectrochemical measurements indicate that the performance of ternary SnS(2-x)Se(x) alloys depends on their band structures and morphology characteristics. Furthermore, SnS(2-x)Se(x) photodetectors present high photoresponsivity with a maximum of 35 mA W(-1) and good light stability in a wide range of spectral response from ultraviolet to visible light, which renders them promising candidates for a variety of optoelectronic applications.

No MeSH data available.


(a) XRD patterns of SnS2−xSex alloys with different Se contents. (b) Enlarged patterns of (a) from 10 to 20 degrees of SnS2−xSex alloys.
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f1: (a) XRD patterns of SnS2−xSex alloys with different Se contents. (b) Enlarged patterns of (a) from 10 to 20 degrees of SnS2−xSex alloys.

Mentions: XRD analysis for SnS2−xSex alloys with different Se contents was performed to examine the change of crystal structure upon Se doping. As shown in Fig. 1, SnSe2 can be indexed with hexagonal CdI2-type unit cells (JCPDS no. 23-0602). The lattice constants of hexagonal SnS2 are a = b = 3.649 Å and c = 5.899 Å (JCPDS no. 23-0677), and the values of SnSe2 are a = b = 3.81 Å and c = 6.14 Å. As expected, the main peak positions of SnS2−xSex alloys gradually shift toward lower angles with increasing Se content (Fig. 1b), indicating the increase of lattice constants and formation of solid solution rather than the mechanical mixture of two pure phases2728. The continuous peak shifting (lattice expanding) of ternary alloys might rule out the phase separation or separated nucleation of SnS2 or SnSe2 nanomaterials2930. As shown in Supplementary Fig. S3 and Table 1, the change of lattice parameter a in SnS2−xSex alloys is in linear with the change of Se content. According to Végard’s Law, the variation of lattice parameters of ternary alloys would present a linear relationship with composition in the absence of strong electronic effects28. Consequently, the variation tendency in SnS2−xSex is in agreement with the Végard’s Law and demonstrates the formation of homogeneous alloy structure31. In additional, the crystallite dimensions of all the samples were calculated by Scherrer equation, which were 12.4 nm, 9.9 nm, 11.5 nm, 12.0 nm, 7.9 nm, and 23.6 nm with the increase of Se contents, respectively (Supplementary Table S1).


Ternary SnS(2-x)Se(x) Alloys Nanosheets and Nanosheet Assemblies with Tunable Chemical Compositions and Band Gaps for Photodetector Applications.

Yu J, Xu CY, Li Y, Zhou F, Chen XS, Hu PA, Zhen L - Sci Rep (2015)

(a) XRD patterns of SnS2−xSex alloys with different Se contents. (b) Enlarged patterns of (a) from 10 to 20 degrees of SnS2−xSex alloys.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
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f1: (a) XRD patterns of SnS2−xSex alloys with different Se contents. (b) Enlarged patterns of (a) from 10 to 20 degrees of SnS2−xSex alloys.
Mentions: XRD analysis for SnS2−xSex alloys with different Se contents was performed to examine the change of crystal structure upon Se doping. As shown in Fig. 1, SnSe2 can be indexed with hexagonal CdI2-type unit cells (JCPDS no. 23-0602). The lattice constants of hexagonal SnS2 are a = b = 3.649 Å and c = 5.899 Å (JCPDS no. 23-0677), and the values of SnSe2 are a = b = 3.81 Å and c = 6.14 Å. As expected, the main peak positions of SnS2−xSex alloys gradually shift toward lower angles with increasing Se content (Fig. 1b), indicating the increase of lattice constants and formation of solid solution rather than the mechanical mixture of two pure phases2728. The continuous peak shifting (lattice expanding) of ternary alloys might rule out the phase separation or separated nucleation of SnS2 or SnSe2 nanomaterials2930. As shown in Supplementary Fig. S3 and Table 1, the change of lattice parameter a in SnS2−xSex alloys is in linear with the change of Se content. According to Végard’s Law, the variation of lattice parameters of ternary alloys would present a linear relationship with composition in the absence of strong electronic effects28. Consequently, the variation tendency in SnS2−xSex is in agreement with the Végard’s Law and demonstrates the formation of homogeneous alloy structure31. In additional, the crystallite dimensions of all the samples were calculated by Scherrer equation, which were 12.4 nm, 9.9 nm, 11.5 nm, 12.0 nm, 7.9 nm, and 23.6 nm with the increase of Se contents, respectively (Supplementary Table S1).

Bottom Line: The variation tendency of band gap was also confirmed by first-principles calculations.The photoelectrochemical measurements indicate that the performance of ternary SnS(2-x)Se(x) alloys depends on their band structures and morphology characteristics.Furthermore, SnS(2-x)Se(x) photodetectors present high photoresponsivity with a maximum of 35 mA W(-1) and good light stability in a wide range of spectral response from ultraviolet to visible light, which renders them promising candidates for a variety of optoelectronic applications.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.

ABSTRACT
Ternary metal dichalcogenides alloys exhibit compositionally tunable optical properties and electronic structure, and therefore, band gap engineering by controllable doping would provide a powerful approach to promote their physical and chemical properties. Herein we obtained ternary SnS(2-x)Se(x) alloys with tunable chemical compositions and optical properties via a simple one-step solvothermal process. Raman scattering and UV-vis-NIR absorption spectra reveal the composition-related optical features, and the band gaps can be discretely modulated from 2.23 to 1.29 eV with the increase of Se content. The variation tendency of band gap was also confirmed by first-principles calculations. The change of composition results in the difference of crystal structure as well as morphology for SnS(2-x)Se(x) solid solution, namely, nanosheets assemblies or nanosheet. The photoelectrochemical measurements indicate that the performance of ternary SnS(2-x)Se(x) alloys depends on their band structures and morphology characteristics. Furthermore, SnS(2-x)Se(x) photodetectors present high photoresponsivity with a maximum of 35 mA W(-1) and good light stability in a wide range of spectral response from ultraviolet to visible light, which renders them promising candidates for a variety of optoelectronic applications.

No MeSH data available.