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Structural and vibrational properties of α- and π-SnS polymorphs for photovoltaic applications
摘要： Tin sulphide (SnS) has attracted the attention of the photovoltaic (PV) community due to the combination of desirable optical properties, and its binary and earth abundant elemental composition, which should lead to relatively simple synthesis. However, currently the best SnS based PV device efficiency remains at 4.36 %. Limited performance of this material is attributed to band gap alignment issues, deviations in doping concentration and poor film morphology. In this context Raman spectroscopy (RS) analysis can be useful as it facilitates the accurate evaluation of material properties. In this study we present a RS study, supported by X-ray diffraction and wavelength dispersive X-ray measurements, of α- and π-SnS thin films. In particular a complete description of SnS vibrational properties is made using six excitation wavelengths, including excitation energies coupled with certain optical band to band transitions, which leads to close to resonance measurement conditions. This study describes an in-depth analysis of the Raman spectra of both SnS structural polymorphs, including the differences in the number of observed peaks, with their relative intensities and Raman shift. Additionally, we evaluate the impact of low temperature heat treatment on SnS. These results explicitly present how the variation of the [S]/[Sn] ratio in samples deposited by different methods can lead to significant and correlated shifts in the relative positions of Raman peaks, which is only observed in the α-SnS phase. Furthermore, we discuss the suitability of using Raman spectroscopy based methodologies to extract fine stoichiometric variations in different α-SnS samples.
关键词： X-ray diffraction,thin films,Raman spectroscopy,SnS
更新于2025-09-12 10:27:22
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Thin film Sn2S3 via chemical deposition and controlled heating - its prospects as a solar cell absorber
摘要： As a semiconductor of “earth-abundant” elements, Sn2S3 with a bandgap (Eg) close to 1 eV merits attention, but a method to prepare phase-pure thin film remains elusive. We report the formation of Sn2S3 thin film of 360 nm in thickness by heating chemically deposited tin sulfide thin films at 450 oC during 30 – 45 min in presence of sulfur at a pressure, 75 Torr of nitrogen. Energy dispersive x-ray emission spectra and grazing incidence x-ray diffraction established a reaction route for this conversion of SnS completely to Sn2S3 via an intermediate phase, SnS2. The optical bandgap of the material is 1.25 eV (indirect) and 1.75 eV (direct, forbidden). The optical absorption suggests a light-generated current density of 30 mA/cm2 for the Sn2S3 film (360 nm) as a solar cell absorber. Thin film Sn2S3 formed in 30 min heating has a p-type electrical conductivity in the dark of 1x10–4 Ω–1 cm–1, which increases to 3x10–4 Ω–1 cm–1 in 0.2 s under 800 W/m2 tungsten-halogen illumination. An estimate made for its mobility-lifetime product is, 6x10–6 cm2 V–1. We discuss the prospects of this material for solar cells.
关键词： SnS-CUB,Sn2S3,semiconductor thin film,chemical deposition,energy conversion,ottemannite,cubic tin sulfide,renewable energy,optical and electrical properties,solar cells
更新于2025-09-11 14:15:04
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Structural, optical and electrical studies of DC-RF magnetron co-sputtered Cu, In & Ag doped SnS thin films for photovoltaic applications
摘要： This work reports the tuning of optical and electrical properties of SnS through the incorporation of Cu, In and Ag atom without altering its chemical and crystal structural properties, using DC-RF magnetron co-sputtering technique with an in-situ substrate temperature of 400 °C. Doping is increased up to ~10% by varying the DC sputtering voltage as evident from EDAX analysis. Morphological studies show the variation in surface morphology, particle size and surface roughness due to the incorporation of dopant cation into SnS lattice sites. Film with optimized doping of ~5% resulted the substitutional doping of dopant cations (Cu2+, In3+ and Ag2+) into SnS lattice sites which resulted an improved absorption coefficient and hall carrier concentration with a decrease in band gap and electrical resistivity. Hall measurement studies of Cu 4.8% doped SnS film shows the p-type conductivity with lowest electrical resistivity of 90 Ω cm and improved carrier concentration of 1017 cm?3.
关键词： SnS thin films,Optical energy band gap,Co-sputtering,Electrical resistivity,Phase formation
更新于2025-09-11 14:15:04
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Development and Fabrication of Improved Josephson Series Arrays with NbSi Barrier for AC Voltage Standards
摘要： Series arrays of overdamped Josephson junctions compose the basis of AC Josephson voltage standards. Presently, an advanced technology is based on Josephson junctions consisting of an NbxSi1-x barrier. Using junction stacks containing five Josephson junctions, series arrays of 15,000 junctions have been successfully fabricated at PTB for the pulse-driven Josephson Arbitrary Waveform Synthesizer (JAWS). The operation of eight arrays simultaneously enable spectrally pure waveforms with output voltages above 1 V to be synthesized.
关键词： SNS Josephson junctions,binary-divided Josephson series arrays,AC Josephson voltage standards,pulse-driven Josephson series arrays,NbSi barrier Josephson junctions
更新于2025-09-10 09:29:36
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X-ray Diffraction Line Profile Analysis of Undoped and Se-Doped SnS Thin Films Using Scherrer’s, Williamson–Hall and Size–Strain Plot Methods
摘要： An electrochemical route has been employed to prepare undoped and Se-doped SnS thin films. Six samples including undoped and Se-doped SnS thin films were deposited on the fluorine-doped tin oxide glass substrate. An aqueous solution containing 2 mM SnCl2 and 16 mM Na2S2O3 was used in the electrolyte. Different Se-doped SnS samples were prepared by adding the various amounts of 4 mM SeO2 solution into the electrolyte. The applied potential (E), time of deposition process (t), pH, and bath temperature (T) were kept at -1 V, 30 min, 2.1, and 60°C, respectively. After the completion of the deposition process, x-ray diffraction (XRD) and transmission electron microscopy (TEM) were utilized to characterize the deposited thin films. XRD patterns clearly showed that the synthesized undoped and Se-doped SnS thin films were crystallized in the orthorhombic structure. Using Scherrer’s method, the crystallite size of deposited thin films is calculated. In addition, the crystallite size and lattice strain have been estimated using the modified form of the Williamson–Hall (W–H) method containing a uniform deformation model, a uniform deformation stress model, a uniform deformation energy density model, and by the size–strain plot method (SSP). The shape of SnS crystals was spherical in TEM images. The results showed that there was a good agreement in the particle size obtained from the W–H method and the SSP method with TEM images.
关键词： thin films,Se-doped SnS,size–strain plot method,Line profile analysis,Williamson–Hall method
更新于2025-09-09 09:28:46
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Fabrication of SnS <sub/>2</sub> /SnS Heterojunction with Enhanced Light-Assisted Electrochemical Water Splitting Performance
摘要： Semiconducting metal sul?des have raised strong research interest among researchers as a promising candidate for light-assisted electrochemical water splitting, because they have wide band gap. In order to harvest more light wavelengths for improvement of light-assisted electrochemical water splitting capacity, we fabricated SnS2/SnS heterojunction nanosheets via facile and environmental route. The SnS2/SnS heterojunction nanosheets were used as photo-electrocatalytic material which exhibited low over potential of ?0.64 V at the current density of 10 mA · cm?2 in 0.5 M NaSO4 solution. Moreover, the SnS and SnS2 nanosheets displayed high over potential values of ?0.80 and ?0.88 V at the current density of 10 mA · cm?2, respectively. This research ?nding may therefore show the potential for use of SnS2/SnS heterojunction nanosheets as low cost and environmentally friendly photo-electrocatalysis.
关键词： SnS2/SnS Heterojunction,SnS2 Nanosheet,SnS Nanosheet,Light-Assisted Electrochemical Water Splitting
更新于2025-09-04 15:30:14