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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.


Electrical and photodetector properties of SnS2−xSex alloys.(a) IDS–VDS curves for the devices. The linearity indicates excellent Ohmic contacts in the SnS2−xSex devices. (b) IDS–VDS curves for SnS0.44Se1.56 device with various illumination power P (λ = 610 nm). The inset shows the logarithmic scale plot of photoresponsivity R as a function of light power (c) The photoresponsivity R of SnS0.44Se1.56 device at different illumination wavelengths (P = 16.36 μW) with a bias voltage of 2 V (red line) and solid phase UV-vis absorption spectrum of SnS0.44Se1.56 alloy (blue line). (d) The time trace of photocurrent response for SnS0.44Se1.56 device at a bias voltage of 2 V (λ = 610 nm, P = 16.36 μW).
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f6: Electrical and photodetector properties of SnS2−xSex alloys.(a) IDS–VDS curves for the devices. The linearity indicates excellent Ohmic contacts in the SnS2−xSex devices. (b) IDS–VDS curves for SnS0.44Se1.56 device with various illumination power P (λ = 610 nm). The inset shows the logarithmic scale plot of photoresponsivity R as a function of light power (c) The photoresponsivity R of SnS0.44Se1.56 device at different illumination wavelengths (P = 16.36 μW) with a bias voltage of 2 V (red line) and solid phase UV-vis absorption spectrum of SnS0.44Se1.56 alloy (blue line). (d) The time trace of photocurrent response for SnS0.44Se1.56 device at a bias voltage of 2 V (λ = 610 nm, P = 16.36 μW).

Mentions: Tin-based chalcogenides have been widely studied as the building blocks for nanoelectronics21434445, which would provide great potentials for next-generation electronic applications. For further extending the optoelectronic applications, we measured the optoelectronic response of as-prepared SnS2−xSex in a wide range from ultraviolet to visible light. A schematic depiction of the devices structure is shown in Supplementary Fig. S10, and the results of electrical and photodetector properties are presented in Fig. 6 and Table 1. At low source-drain voltage, the IDS–VDS curves of all devices are symmetric and linear, indicating the Ohmic contacts between Au electrodes and SnS2−xSex films. The currents present significant enhancement with the increasing Se content, which might be attributed to the synergistic influence of morphology and tunable electronic structure. The SnS0.44Se1.56 film shows highest current values. Its unique 2D configuration (large dimension of 1.8−2.5 μm and thin thickness of ca. 8 nm) would provide more active sites and shorter route in electronic transfer process. Furthermore, the photoresponse measurements for SnS0.44Se1.56 alloy were carried out. Figure 6b provides IDS vs VDS curves of SnS0.44Se1.56 device without and with red light illumination (λ = 610 nm) with various power intensity. With increasing power intensity, the photocurrent distinctly increases, which could be ascribed to the increasing number of photogenerated carriers. The photoresponsivity R, defined as the ratio between photocurrent increase (ΔI) and power intensity (P), ΔI/P, as a function of illumination power is shown in the inset of Fig. 6b. It is clear that R decreases with the increase of laser power, which may be attributed to the enhanced scattering or recombination rate of hot carriers at higher laser power intensity20. The relationship between photoresponsivity versus incident light power can be fitted by a power law relationship R ∝ Pα−1204647. The fitting parameter α = 0.80 was obtained in our measurement, which is comparable to that of layered SnS2 (α = 0.77)20 and few-layer MoS2 (α = 0.71)46, indicating that the recombination kinetics of photogenerated carriers is related to both trap states and interaction of carriers47.


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)

Electrical and photodetector properties of SnS2−xSex alloys.(a) IDS–VDS curves for the devices. The linearity indicates excellent Ohmic contacts in the SnS2−xSex devices. (b) IDS–VDS curves for SnS0.44Se1.56 device with various illumination power P (λ = 610 nm). The inset shows the logarithmic scale plot of photoresponsivity R as a function of light power (c) The photoresponsivity R of SnS0.44Se1.56 device at different illumination wavelengths (P = 16.36 μW) with a bias voltage of 2 V (red line) and solid phase UV-vis absorption spectrum of SnS0.44Se1.56 alloy (blue line). (d) The time trace of photocurrent response for SnS0.44Se1.56 device at a bias voltage of 2 V (λ = 610 nm, P = 16.36 μW).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
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f6: Electrical and photodetector properties of SnS2−xSex alloys.(a) IDS–VDS curves for the devices. The linearity indicates excellent Ohmic contacts in the SnS2−xSex devices. (b) IDS–VDS curves for SnS0.44Se1.56 device with various illumination power P (λ = 610 nm). The inset shows the logarithmic scale plot of photoresponsivity R as a function of light power (c) The photoresponsivity R of SnS0.44Se1.56 device at different illumination wavelengths (P = 16.36 μW) with a bias voltage of 2 V (red line) and solid phase UV-vis absorption spectrum of SnS0.44Se1.56 alloy (blue line). (d) The time trace of photocurrent response for SnS0.44Se1.56 device at a bias voltage of 2 V (λ = 610 nm, P = 16.36 μW).
Mentions: Tin-based chalcogenides have been widely studied as the building blocks for nanoelectronics21434445, which would provide great potentials for next-generation electronic applications. For further extending the optoelectronic applications, we measured the optoelectronic response of as-prepared SnS2−xSex in a wide range from ultraviolet to visible light. A schematic depiction of the devices structure is shown in Supplementary Fig. S10, and the results of electrical and photodetector properties are presented in Fig. 6 and Table 1. At low source-drain voltage, the IDS–VDS curves of all devices are symmetric and linear, indicating the Ohmic contacts between Au electrodes and SnS2−xSex films. The currents present significant enhancement with the increasing Se content, which might be attributed to the synergistic influence of morphology and tunable electronic structure. The SnS0.44Se1.56 film shows highest current values. Its unique 2D configuration (large dimension of 1.8−2.5 μm and thin thickness of ca. 8 nm) would provide more active sites and shorter route in electronic transfer process. Furthermore, the photoresponse measurements for SnS0.44Se1.56 alloy were carried out. Figure 6b provides IDS vs VDS curves of SnS0.44Se1.56 device without and with red light illumination (λ = 610 nm) with various power intensity. With increasing power intensity, the photocurrent distinctly increases, which could be ascribed to the increasing number of photogenerated carriers. The photoresponsivity R, defined as the ratio between photocurrent increase (ΔI) and power intensity (P), ΔI/P, as a function of illumination power is shown in the inset of Fig. 6b. It is clear that R decreases with the increase of laser power, which may be attributed to the enhanced scattering or recombination rate of hot carriers at higher laser power intensity20. The relationship between photoresponsivity versus incident light power can be fitted by a power law relationship R ∝ Pα−1204647. The fitting parameter α = 0.80 was obtained in our measurement, which is comparable to that of layered SnS2 (α = 0.77)20 and few-layer MoS2 (α = 0.71)46, indicating that the recombination kinetics of photogenerated carriers is related to both trap states and interaction of carriers47.

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.