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Band structure and optical constants of SnS <sub/>2</sub> single crystals
摘要： Absorption (K), reflection (R) and wavelength modulated transmission (ΔT/Δλ) spectra in SnS2 crystals of hexagonal phase (space group P63/mmc) were investigated in temperature interval from 300 to 10 K. It was established that indirect band gap (Eg ind - 2.403 eV) is due to unpolarized indirect transitions between Γ and M points of Brillouin zone. A minimal direct band gap (Eg dir - 2.623 eV) in E||b polarization is formed by direct allowed transitions and in E⊥b polarization (2.698 eV) by forbidden transitions in Γ point of Brillouin zone. A magnitude of refractive index (n) changes from 3 to 4 and has a maximum at 2.6 eV. Optical functions (n, k, ε1 and ε2) in energy region E > Eg (3 - 6.5 eV) were calculated from measured reflection spectra by Kramers-Kronig analysis. Features observed in reflection and optical function spectra were assigned to electron transitions. This electron transitions were localized in framework of theoretically calculated band structure.
关键词： optical functions,electronic band structure,layered SnS2 crystals,absorption, reflection and transmission spectra
更新于2025-09-23 15:23:52
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Ammonia sensing properties of two-dimensional tin disulphide/tin oxides (SnS2/SnO2-x) mixed phases
摘要： 2D-SnS2 flakes were synthesized via a wet chemical route and deposited as a thin film onto the Pt-interdigitated contacts of a ceramic substrate with aim to fabricate a conductometric sensor. The 2D-SnS2 sensing film was then annealed "in situ" under controlled conditions at different temperatures up to 400 °C. The morphological, microstructural and electrical properties of the sensing film, before and after the thermal treatment, were characterized by "in situ" techniques. SEM analysis has shown that the 2D flake morphology was maintained after thermal treatments, whereas Raman and EDX analysis have highlighted the partial/total modification of the SnS2 phase towards the SnO2. As a consequence of the formation of 2D-SnS2/SnO2-x mixed phases, a dramatic change of the electrical properties of the sensing film has been also observed. Conductometric gas sensors based on hybrid SnS2-SnO2-x nanoflakes were then obtained by simple self-annealing treatments of 2D-SnS2 film directly on the sensor substrate. The fabricated sensors were tested toward ammonia (NH3) as target gas. Results evidence that increasing the annealing temperature of the 2D-SnS2 sensitive film, the electrical resistance of the sensing layer decreases while the response towards ammonia increases, showing the maximum at an annealing treatment of 250 °C. This behaviour was explained on the basis of the morphological, microstructural and electrical modifications observed, highlighting the role of 2D-SnS2/SnO2-x mixed phases in determining the sensing properties towards ammonia.
关键词： Heterostructure,Gas sensor,NH3,2D-SnS2 flakes,Ammonia
更新于2025-09-23 15:23:52
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Evidencing enhanced charge-transfer with superior Photocatalytic degradation and Photoelectrochemical water splitting in Mg modified few-layered SnS2
摘要： Recently there has been immense interest in the exploration of richly available two-dimensional non-toxic layered material such as tin disulfide (SnS2) for potential employment in energy and environmental needs. In this regard, we report on the synthesis of few-layered Sn1?xMgxS2 nanosheets through a facile one-step hydrothermal route to address all such functions concerning photocatalysis and photoelectrochemical conversion. The crystalline order and structure of processed layered Sn1?xMgxS2 were initially found to exhibit a strong influence on their physicochemical properties. Their optical properties attest the Mg doping in SnS2 to benefit us with enhanced visible-light absorption via red-shift in their absorption edge. In the photoluminescence spectrum the emissions observed along visible and red region signifies the association of Mg related trap states in Sn1?xMgxS2. Next, the photocurrent and electrochemical impedance spectroscopic results revealed the Mg doping to promote the effective charge transfer process (which was beneficial to enhance their photocatalytic activity). Consequently, the layered Sn0.98Mg0.02S2 made photoanodes displayed 1.7 fold higher photocurrent density under simulated solar radiation with respect to their undoped counterpart. Furthermore, the layered Sn0.98Mg0.02S2 nanosheets exhibits enhanced visible light decomposition of organic dye while compared with pristine SnS2 nanosheets. The value of rate constants obtained for the Sn0.98Mg0.02S2 nanosheets was found to be 1.4 times higher than that of pristine SnS2. Finally, the results obtained through the present study projects the huge potential of layered Sn0.98Mg0.02S2 nanosheets for future multifunctional applications.
关键词： SnS2,Magnesium,Nanosheets,Photocatalysis,Few-layered,Photoelectrochemical water splitting
更新于2025-09-23 15:22:29
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Surfactant-free stable SnS2 nanoparticles dispersion for deposition of device-quality films
摘要： Tin sulfide (SnS2) has recently attracted considerable attention due to its layered structure that may form two dimensional morphologies. It is an n-type semiconductor with band gap and electron affinity similar to CdS and In2S3; therefore can be regarded as an alternative for these materials in thin film solar cells. Here, we synthesis of SnS2 nanoparticles with different morphology in different ratio of water-ethanol mixed solution by solvothermal method, and observe that more ethanol leads to large sheet like morphologies, while water based synthesis results in very small nanosheets. A challenge in wet deposition of device-quality thin films of SnS2 is the requirement for highly dispersed particles/sheets. We found highly polar dimethylformamide (DMF) as the right dispersing medium, yielding highly stable dispersions. Very uniform nanocrystalline thin films with [001] preferred orientation and good adhesion to substrate are simply deposited by drop casting and spin coating a 0.5 wt% DMF sol of SnS2 at 2000 rpm for 1 min. Electron affinity and band gap of the films are 4.33 eV and 2.27 eV, which is well aligned for copper indium gallium sulfo-selenide (CIGS) solar cells.
关键词： Two dimensional structures,Surfactant-free dispersion,copper indium gallium sulfo-selenide solar cells,SnS2 thin film,Dimethylformamide,Buffer layer
更新于2025-09-23 15:21:21
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2D-SnS$_2$ Nanoflakes Based Efficient Ultraviolet Photodetector
摘要： This paper reports a SnS2 nanoflakes based UV photodetector having high sensitivity and thermal stability upto 120 ?C. Simple and low cost solvothermal technique has been used to synthesize SnS2 nanoflakes of close to hexagonal shapes. A simple photoconductor structure on SiO2/Si substrate is fabricated by using Ag as contact material. The resultant device has good sensitivity (～400), responsivity (～5.5 A/W), EQE (～1868%), detectivity (～1.72 × 1013 Jones) and low response time (～2.2 s). The reported characteristics are superior to many other UV photodetectors utilizing complex hybrid structure of the device, either in form of additional filter layer or nanostructural light sensitive material.
关键词： photoconductor,UV photodetector,SnS2 nanoflakes,2-D material
更新于2025-09-23 15:21:01
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Impact of Al2O3 stress liner on two-dimensional SnS2 nanosheet for photodetector application
摘要： Layered tin disulfide (SnS2) nanosheets are gradually coming into people’s vision as an emerging two-dimensional material for the potential application majority in optoelectronic field. We investigate a sample of ultra-thin SnS2 nanosheets (~5 nm) on SiO2/Si substrates and the photodetectors performance based on it with and without high-k ALD-Al2O3 stress liner. By means of temperature-dependent Raman spectroscopy, both a red-shift of Raman frequency from 313.1 cm-1 to 311.2 cm-1 as well as a reduction of the first order temperature coefficient from -0.01232 cm-1/K to -0.00895 cm-1/K are measured. For device, compared to SnS2 photodetector, Al2O3/SnS2 photodetector shows enhancement with 7-times light current, 10-times responsivity, 25%-off rising time and 70%-off falling time under 365 nm illumination. The phenomena can be rationalized by factors that the SnS2 sample suffers a tensile strain and passivation effect exerted by capped Al2O3 layer. Meanwhile, the first principle calculations assist the study from an angle of verification. The analogue stress treatment operated in this work improves the properties of SnS2 and enhances the performances of SnS2-based photodetectors, aiming at expanding the thin-film materials applications in optoelectronic devices.
关键词： Al2O3 stress liner,Photodetector,SnS2,Raman spectroscopy
更新于2025-09-23 15:19:57
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Gianta??Enhanced SnS <sub/>2</sub> Photodetectors with Broadband Response through Oxygen Plasma Treatment
摘要： Layered tin disulfide (SnS2) is a vital semiconductor with versatile functionality due to its high carrier mobility and excellent photoresponsivity. However, the intrinsic defects Vs (sulfur vacancies), which cause Fermi level pinning (significant metal contact resistance), hinder its electrical and optoelectrical performance. Herein, oxygen plasma treatment is employed to enhance the optoelectronic performance of SnS2 flakes, which results in artificial sub-bandgap in SnS2. Consequently, the broadband photosensing (300–750 nm) is remarkably improved. Specifically, under 350 nm illumination, the O2-plasma-treated SnS2 photodetector exhibits an enhanced photoresponsivity from 385 to 860 A W?1, the external quantum efficiency and the detectivity improve by one order of magnitude as well as increase the photoswitching response improvement by two orders of magnitude for both rising (τr) and decay (τd) time. This artificial sub-bandgap can both improve the photoresponse and broaden the response spectra, which paves a new path for the applications of optoelectronics.
关键词： broadband photodetection,2D materials,SnS2 photodetectors,oxygen plasma treatment
更新于2025-09-23 15:19:57
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Solution-processed ultrathin SnS <sub/>2</sub> -Pt nanoplates for photoelectrochemical water oxidation
摘要： Tin disulfide (SnS2) is attracting significant interest due to the abundance of its elements and its excellent optoelectronic properties in part related to its layered structure. In this work, we detail the preparation of ultrathin SnS2 nanoplates (NPLs) through a hot-injection solution-based process. Subsequently, Pt was grown on their surface via in-situ reduction of a Pt salt. The photoelectrochemical (PEC) performance of such nanoheterostructures as photoanode toward water oxidation was afterward tested. Optimized SnS2-Pt photoanodes provided significantly higher photocurrent densities than bare SnS2 and SnS2-based photoanodes previously reported. Mott-Schottky analysis and PEC impedance spectroscopy (PEIS) were used to analyze in more detail the effect of Pt on the PEC performance. From these analyses, we attribute the enhanced activity of the SnS2-Pt photoanodes here reported to a combination of the very thin SnS2 NPLs and the proper electronic contact between Pt nanoparticles (NPs) and SnS2.
关键词： photoanode,Tin disulfide,SnS2-Pt heterostructure,two-dimensional material,photoelectrochemical water oxidation
更新于2025-09-19 17:15:36
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Q-switched mode-locked Nd:GGG waveguide laser with tin disulfide as saturable absorber
摘要： We demonstrate a Q-switched mode-locked waveguide laser operation with high fundamental repetition rate based on the few-layer tin disulfide (SnS2) as a saturable absorber. The excellent nonlinear optical property of SnS2 enables efficient pulsed laser generation. By using Nd:GGG ridge waveguide, the fundamental repetition rate up to 17.9 GHz has been achieved for the mode-locked pulses with duration as short as 30 ps. In addition, this Nd:GGG-based waveguide laser exhibits excellent lasing properties (maximum output power of 115 mW at 1064 nm) by modulation of SnS2, suggesting promising application as miniature ultrafast light sources.
关键词： Waveguide lasers,Tin disulfide (SnS2),Nd:GGG crystal,Q-switched mode-locked laser
更新于2025-09-19 17:13:59
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Controlled synthesis of SnSxSe2?x nanoplate alloys via synergetic control of reactant activity and surface defect passivation control with surfactant and co-surfactant mixture
摘要： Two-dimensional (2D) metal dichalcogenide nanomaterials have been receiving enormous research interest for electronic, optoelectronic, and catalytic applications. However, the facile tunability of alloying and doping, as well as the successful formation of ideal defect-free nanoplate morphology have been hardly achieved for 2D nanomaterials. Herein, we successfully synthesized a series of 2D solid-solution SnSxSe2(cid:1)x particles of 0.20–2.00 μm width and 30–68 nm thickness with morphological defect-free nanoplate via a solvothermal reaction. With controlled reactivities of elemental chalcogen precursors, a co-surfactant hexylamine together with a structure-directing agent polyvinylpyrrolidone was found to be essential for realizing ideal defect-free nanoplate morphology of SnSxSe2(cid:1)x particles without either cabbage-like or twinned structure. The successful synthesis of morphologically defect-free SnSxSe2(cid:1)x nanoplates with rationally controlled energy band gaps ranging from 1.36 eV for SnSe2 to 1.96 eV for SnS2 could provide promising materials for electronics, optoelectronics, and electrocatalytic applications.
关键词： 2D nanomaterials,Nanoplate,SnSe2,SnS2,Band gap,SnSxSe2(cid:1)x
更新于2025-09-19 17:13:59