Sn Precursor Research Articles

Effect of the different types of Sn-precursors on the properties of Sn FeMgAl-LDH samples

In this work, LDH SnFeMgAl were prepared by co-precipitation method at constant temperature and pH using different Sn precursors. Calcined and LDHs samples were then determined for their chemical, structural, acid-base, and textural properties by XRD, SEM-EDX, TGA-MS, DRIFT, N₂ physisorption, NH₃-TPD, CO₂-TPD and the Baeyer–Villiger (BV) oxidation of myrtenal. Since turbidity often occurs in tin doped LDH, the goal of this work was to find a way to use another precursor that eliminates the turbidity problem. It was found that the choice of tin precursor had a significant effect on the acid-base properties of the obtained LDH materials and thus on their catalytic activity. All prepared catalysts were active both for the BV oxidation of myrtenal itself and for the subsequent hydrolysis of the formed formate to nopinone. The best results were obtained using FeMgAl LDH in the presence of the meta-chloroperoxybenzoic acid (mCPBA) and mixed oxide FeMgAl LDH-C in the presence of H₂O₂. In terms of nopinone yield, SnFeMgAl(Cl−)-C proved to be the best catalyst, which also had the highest proportion of acid and basic active sites among all the catalysts investigated.

Evaluation of tin nitride (Sn3N4) via atomic layer deposition using novel volatile Sn precursors.

Novel Sn precursors, Sn(tbip)2, Sn(tbtp)2, and Sn(tbta)2, were synthesized and characterized using various analytical techniques and density functional theory calculations. These precursors contained cyclic amine ligands derived from iminopyrrolidine. X-ray crystallography revealed the formation of monomeric SnL2 with distorted seesaw geometry. Thermogravimetric analysis demonstrated the exceptional volatility of all complexes. Sn(tbtp)2 showed the lowest residual weight of 2.7% at 265 °C. Sn3N4 thin films were successfully synthesized using Sn(tbtp)2 as the Sn precursor and NH3 plasma. The precursor exhibited ideal characteristics for atomic layer deposition, with a saturated growth per cycle value of 1.9 Å cy-1 and no need for incubation when the film was deposited at 150-225 °C. The indirect optical bandgap of the Sn3N4 film was approximately 1-1.2 eV, as determined through ultraviolet-visible spectroscopy. Therefore, this study suggests that the Sn3N4 thin films prepared using the newly synthesized Sn precursor are suitable for application in thin-film photovoltaic devices.

Preparation of highly dispersed SnO/TiO2 catalysts and their performances in catalyzing polyol ester.

A series of stannous oxide supported on rutile titanium dioxide (SnO/TiO2) were prepared by a conventional incipient wetness impregnation method, and their performance as catalysts for fatty acid esterification reactions was investigated. The effects of Sn precursors (SnCl2·2H2O or SnC2O4), loading amounts (5-15%), and treating ambiences (air and N2) were explored. The optimized 10% SnO/TiO2-Cl with SnCl2·2H2O as the Sn precursor and thermal treatment in N2 showed the best esterification performance. Specifically, 10% SnO/TiO2-Cl catalyzed the esterification process of trimethylolpropane and n-octanoic acid with a conversion of 99.6% over 5 h at 160 °C, and 10% SnO/TiO2-Cl was efficient for six catalytic cycles. Based on the results of X-ray diffraction (XRD), Raman spectra, high-resolution transmission electron microscopy (HRTEM), infrared spectra of pyridine adsorption (Py-IR), and ammonia temperature programmed desorption (NH3-TPD), the improved catalytic performance is supposed to be attributable to the high dispersion of the Sn species on 10% SnO/TiO2-Cl as the moderate Lewis acid sites.

Multi-pulse atomic layer deposition of p-type SnO thin films: growth processes and the effect on TFT performance

P-type SnO thin films have been deposited using multiple pulses of a novel Sn(ii) precursor per ALD cycle. The study looks at the effect on TFT performance and AFM analysis has explored the change in the growth processes during deposition.

Controllable synthesis of Sn0.33WO3 tungsten bronze nanocrystals and its application for upconversion luminescence enhancement

The development and utilization of novel semiconductor nanocrystals with remarkable localized surface plasmon resonance (LSPR) effect is one of the current research hotspots. Tungsten bronze nanocrystals are a class of semiconductor nanocrystals with strong LSPR effect discovered recently. The synthesis of tungsten bronze nanocrystals by introducing high valence metal ions, the regulation and application of the corresponding LSPR effect are still under further exploration. In this paper, Sn 0.33 WO 3 nanocrystals with different crystal phases and morphologies were synthesized using different types of Sn precursors and different amounts of NH 4 F. Acid radical ions provided by different types of Sn precursors is an important factor affecting the LSPR absorption characteristics of Sn 0.33 WO 3 nanocrystals. Sn 0.33 WO 3 nanosheets with strong LSPR absorption synthesized with stannous oxalate were used as a representative to enhance the upconversion luminescence of NaYF 4 :Yb 3+ , Er 3+ . Compared with Glass/NaYF 4 :Yb 3+ , Er 3+ film, the upconversion luminescence intensity of the layered Glass/Sn 0.33 WO 3 /PMMA/NaYF 4 :Yb 3+ , Er 3+ film was enhanced by 34 times. The LSPR effect of Sn 0.33 WO 3 enhances the excitation field of NaYF 4 :Yb 3+ , Er 3+ nanocrystals, resulting in significant upconversion luminescence enhancement of NaYF 4 :Yb 3+ , Er 3+ in the layered Glass/Sn 0.33 WO 3 /PMMA/NaYF 4 :Yb 3+ , Er 3+ film. The present work is helpful for people to study the development and application of semiconductor nanocrystals with LSPR effect.

X-ray tomography assessment of the heat treatment effect on Nb3Sn wires with different architectures

Two unreacted commercially available Nb 3 Sn precursor wires with different architecture were subject to a two-temperature heat treatment in vacuum at 650 °C for 72 h and at 700 °C for 168 h. Evolution of wires towards formation of the superconducting phase was assessed by the non-invasive X-ray computed microtomography (micro XRT) with a spatial resolution of ∼2 μm on the samples before and after the heat treatments. Statistical image analysis quantified the defects and quantitatively revealed the deviation of the geometrical perfection of the wire components comparative to designed parameters depending on the wire architecture and heat treatment conditions. Our results position XRT as a tool to evaluate the quality of Nb 3 Sn, also promoting it as a method capable for providing new insights that could be used in the optimization processes of Nb 3 Sn wires design, technology, and during operation. • Wires of Nb 3 Sn were heat treated (HT) and assessed by x-ray tomography (XRT). • Before and after HT, defects and deviation from design parameters were quantified. • Architecture has a strong influence on the HT processes and quality of the wires. • XRT emerges as a non-invasive tool with novel, unique characterization possibilities. • XRT contributes wires optimization, fabrication, application, and during operation.

In situ construction of SnO-NiO derived from metal-organic frameworks on nickel foam for energy storage devices

Background: Metal-organic frameworks (MOFs) have concerned substantial research attention as potential electrode materials in the field of electrochemical storage owing to their high porosity. However, their low cycling stability and rapid capacity fading hinder the practical application of MOFs because of the structural instability of the electrodes during cycling. Existing studies have shown that MOF-derived materials are helpful in improving their performance due to controllable functionalities, permanent porosities, and high surface area.Methods: We demonstrated an efficient strategy to solve these problems by combining the beneficial redox properties of Sn and Ni metal precursor and benzene-1,3,5-tricarboxylate (BTC) organic linker. SnONiO derived from Sn-Ni MOFs were in situ deposited on nickel foam (i.e., Sn-Ni MF@Ni nanostructures) by solvo-hydrothermal approach.Significant findings: The all-solid-state asymmetric supercapacitor device, Sn-Ni MF@Ni//AC, exhibited excellent electrochemical storage capacity (214.67 F/g at 1.0 A/g) and excellent high-rate cycling stability of 90% over 6000 cycles. The Sn-Ni MF@Ni//AC nanostructured device exhibited high energy and power densities of 66.87 Wh/kg at 747.67 W/kg, respectively, at a discharge time of 322 s. The remarkable electrochemical storage properties of Sn-Ni MF@Ni nanostructures can be attributed to their unique SnO and NiO bimetallic oxide phases on NF substrates. They are comparable to those of drop-cast Sn-Ni MFs on NF electrodes.

Low Pressure Growth of Pseudomorphic Gesn with 16.7% Sn Incorporation

Alloys of GeSn offer promising optical advantages for high performance optoelectronic device applications monolithically integrated on Si operating in the near and mid-infrared spectrum. Investigations worldwide into the growth of GeSn alloys using various Ge and Sn precursors in conjunction with the chemical vapor deposition growth technique has been reported. The use of higher order Ge hydrides and/or higher growth pressures above 40 torr have been investigated to achieve relatively high incorporations of Sn. In this work, we successfully demonstrated the low pressure growth at 12 torr of GeSn alloy with 16.7% Sn composition. Instead of using a higher order Ge precursor, the alloy was grown via chemical vapor deposition using the commercially available percussors GeH4 and SnCl4. Material and optical characterizations were performed to study the crystalline quality and optical properties. The growth results demonstrate a novel growth window in the low pressure regime to achieve high Sn composition alloy material with high quality for the use in future devices and applications.

(Si)GeSn Isothermal Multilayer Growth for Specific Applications Using GeH4 and Ge2H6

The experimental demonstration of Ge1-xSnx alloys lasers opened group-IV materials towards high-performance electronic and photonic devices that can be easily integrated with the current Si semiconductor technology. In recent years, GeSn-based optoelectronic devices including light-emitting and detectors, modulators, and CMOS have been proven.The major challenges for the Ge1-xSnx epitaxy arise from the low solid solubility of Sn in Ge, the large lattice mismatch, and the reduced thermal stability between Ge and Sn. All these are becoming extremely critical at higher Sn contents. Non-equilibrium conditions offered by molecular beam epitaxy (MBE), chemical vapor deposition (CVD), flash lamp, or laser annealing have been lately investigated. Between them, CVD is to date the preferred growth technique for its current development compatible with the industry offering micron-thick layers with the highest crystal quality.While Tin-tetrachloride (SnCl4) becomes the standard Sn precursor, for Ge different gasses, like germane (GeH4) and digermane (Ge2H6) are used attempting to archive high Sn incorporation and high material quality. While Ge1-xSnx films with the same high Sn content can be obtained regardless of the used precursor, the advantages and disadvantages of each precursor are discussed in this work. The use of Ge2H6 is accompanied by high growth rates, being favorable in applications where relatively thick films are needed, such as laser structures. On the other hand, with a relatively low growth rate, GeH4 provides a greater thickness control, achieving clear and sharp interfaces in heterostructures. For this reason, GeH4 is the appropriate precursor for quantum transport or spintronic.The biggest challenge in heterostructure designs is going up and down in Sn content. The growth of a Ge1-ySny on a Ge1-xSnx, y<x, or SiGeSn layer cannot be performed by increasing the growth temperature. Post-annealing processes lead to strong crystallinity degradation of the already grown layer by strong Sn diffusion or Sn segregation due to the limited thermal stability of Ge1-xSnx alloys.In this work, we address simple methodologies to enhance the gradient or step Sn content without changing the process temperature. Controlling only the carrier gas flow while keeping the standard growth parameters constant, high-quality Ge1-xSnx alloys with uniform Sn content up to 15 at.% are obtained. The proposed method acts as guidance to produce Ge1-xSnx heterostructures that can be extended to any CVD reactor, independently of the used precursor, GeH4 or Ge2H6. Different devices structures are presented proving the applicability of the isothermal multilayer growth. Figure 1

Supernova Precursor Emission and the Origin of Pre-explosion Stellar Mass Loss

A growing number of core-collapse supernovae (SNe) that show evidence for interaction with dense circumstellar medium (CSM) are accompanied by “precursor” optical emission rising weeks to months prior to the explosion. The precursor luminosities greatly exceed the Eddington limit of the progenitor star, implying that they are accompanied by substantial mass loss. Here, we present a semi-analytic model for SN precursor light curves, which we apply to constrain the properties and mechanisms of the pre-explosion mass loss. We explore two limiting mass-loss scenarios: (1) an “eruption” arising from shock breakout following impulsive energy deposition below the stellar surface; and (2) a steady “wind,” due to sustained heating of the progenitor envelope. The eruption model, which resembles a scaled-down version of Type IIP SNe, can explain the luminosities and timescales of well-sampled precursors, for ejecta masses ∼ 0.1–1 M ⊙ and velocities ∼ 100–1000 km s−1. By contrast, the steady wind scenario cannot explain the highest precursor luminosities ≳ 1041 erg s−1, under the constraint that the total ejecta mass does not exceed the entire progenitor mass (though the less luminous SN 2020tlf precursor can be explained by a mass-loss rate ∼ 1 M ⊙ yr−1). However, shock interaction between the wind and pre-existing (earlier ejected) CSM may boost its radiative efficiency and mitigate this constraint. In both the eruption and wind scenarios, the precursor ejecta forms compact (≲1015 cm) optically thick CSM at the time of core collapse; though only directly observable via rapid post-explosion spectroscopy (≲ a few days before being overtaken by the SN ejecta), this material can boost the SN luminosity via shock interaction.

Controllable Synthesis of Atomically Thin 1T‐SnSe2 Flakes and Its Linear Second Harmonic Generation with Layer Thickness

AbstractAs an important member of the IVA–VIA group compounds, 2D SnSe2 has emerged as a perfect platform for developing diverse applications, especially in high‐performance optoelectronic devices and data storage, etc. However, the bottom‐up synthesis of large‐area uniform, atomically thin SnSe2 crystals with controlled thicknesses has not yet been realized. Herein, we report the large‐area uniform growth of monolayer (1L), bilayer (2L), and few‐layer (FL) 1T‐SnSe2 single‐crystal flakes on mica substrates via a facile chemical vapor deposition (CVD) route. The feeding amount of Sn precursor and flow rate of hydrogen carrier are found to be the key parameters for the thickness‐controlled growth of uniform SnSe2 flakes. More intriguingly, obvious second harmonic generation (SHG) is revealed in the retained inversion symmetry structure of 1T‐SnSe2, with its intensity showing linear dependence with the thickness from monolayer to multilayers. The new findings reported herein should pave the ways for the thickness‐tunable growth of atomically thin SnSe2 crystals, and their unique optical property explorations and applications in nonlinear optics.

Chemical Bath Deposited Orthorhombic SnS Films for Solar Cell Applications

Tin sulfide (SnS) thin films were deposited by the chemical bath deposition technique. The used procedure allows us to obtain orthorhombic SnS in 3.5 h and achieve thicknesses of 390 nm. We study the influence of deposition times, percentage of Sn precursor, and post-annealing on the structural and optical properties. The X-ray diffraction measurements of SnS films prepared at a deposition time of 3 h showed orthorhombic structure with characteristic peaks of SnS2. However, increasing the deposition time and the Sn precursor, the orthorhombic SnS phase in these samples becomes predominant. Thin-film morphologies and thicknesses were identified by scanning electron microscopy (SEM). An increase in bandgap from 1.41 eV to 1.56 eV was observed by increasing Sn precursor. The optical properties remain constant after air annealing of 285 °C. Low-temperature photoluminescence spectra show emission bands at 2.5 eV attributed to the presence of SO2. Other deep level transitions were observed at about 0.9 eV, probably due to oxygen.

Influence of sulfurization time and Cu-ZnS-Sn stack order on the properties of thermally evaporated CZTS thin films

Cu2ZnSnS4 (CZTS) thin films were synthesized in a two-step procedure. Sulfurization of stacked thin films SLG/ZnS/Sn/Cu (S1) and SLG/Cu/Sn/ZnS (S2) after sequential deposition of Cu, ZnS, and Sn precursors was carried out. At 550 °C, two sulfurization periods were applied to both stack orders. Sample S1 sulfurized for 30 min (S1-T30) had a better crystallite size of roughly 50 nm, lower lattice strain, and lower dislocation density than other samples. The Cu/Zn cation ordering in the CZTS crystal system was significantly affected by stack sequence and sulfurization time, according to Q-factor calculation. The stack order of the S1 series allowed for homogenous and distinct particle development. From the elemental analysis, it is observed that the stack sequence and sulfurization used for sample S1-T30 permitted a near stoichiometric composition. The sample S1-T30 exhibited an optimal band gap value of 1.47 eV. To propose feasible alterations in the structural ordering, band gap calculations were used. In comparison to the stack order of the S2 series, the stack order SLG/ZnS/Sn/Cu with a sulfurization time of 30 min created a single-phase CZTS, implying less synthesis time to obtain an absorber quality CZTS layer for solar photovoltaic application.

Growth of Pseudomorphic GeSn at Low Pressure with Sn Composition of 16.7.

Group-IV alloy GeSn holds great promise for the high-performance optoelectronic devices that can be monolithically integrated on Si for near- and mid-infrared applications. Growth of GeSn using chemical vapor deposition technique with various Sn and Ge precursors has been investigated worldwide. To achieve relatively high Sn incorporation, the use of higher pressure and/or higher order Ge hydrides precursors were reported. In this work, we successfully demonstrated the growth of high-quality GeSn with Sn composition of 16.7% at low pressure of 12 Torr. The alloy was grown using the commercially available GeH4 and SnCl4 precursors via a chemical vapor deposition reactor. Material and optical characterizations were performed to confirm the Sn incorporation and to study the optical properties. The demonstrated growth results reveal a low-pressure growth window to achieve high-quality and high Sn alloys for future device applications.

Sulfurization temperature dependent properties of tin mono-sulfide thin films

Tin mono-sulfide thin films were prepared using a two-step process consisting of DC sputtered deposition of Sn precursors over glass substrate held at 150 oC, followed by sulfurization for 1 hour at different temperatures ranging from 250 oC to400 oC. The influence of the sulfurization temperature on resultant films was studied in terms of its structure, morphology and opto-electronic properties. X-ray diffraction study revealed that the films sulfurized at lower temperature (~250 oC) had prominent SnS2 phase in addition to SnS. A single-phase tin mono-sulfide planes corresponding to orthorhombic structure has been observed at 300 oC and found to be highly crystalline at 350 oC. Further, three distinct Raman modes observed at 95, 190 and 218 cm-1 for Sn precursors sulfurized at 350 oC, strongly supporting the formation of single phase SnS. The optimized SnS film showed a direct band gap of 1.35 eV with an absorption coefficient of 5 x 104 cm-1. The valence states of Sn (+2) and S (-2) determined from X-ray photoelectron spectroscopy analysis for Sn precursors sulfurized at 350 oC, indicating the existence of SnS. These films had stoichiometric atomic ratio of Sn/S ~ 1 with surface roughness of 20 nm. All the films have shown p-type conductivity and the Sn precursors sulfurized at 350 oC exhibited relatively high conductivity of 0.947 x 10-2 (Ω cm)-1. The optoelectronic properties of SnS films reported in the present work would be highly suitable for device fabrication and promising as an alternative absorber for thin film solar cells. Copyright © 2017 VBRI Press.

Polycrystalline and high purity SnO2 films by plasma-enhanced atomic layer deposition using H2O plasma at very low temperatures of 60–90 °C

High-quality SnO2 films with excellent crystallinities, purities, and high densities grown at low deposition temperatures (<100 °C) are essential owing to their applications in flexible electronics and energy devices. In this work, we successfully demonstrated plasma-enhanced atomic layer deposition (PEALD) of SnO2 films at very low deposition temperatures of 60–90 °C using dimethylamino-2-methyl-2-propoxy-tin(II) (Sn(dmamp)2) and H2O plasma as the Sn precursor and reactant, respectively. These films showed a high growth per cycle of 0.24–0.30 nm/cycle owing to the excellent reactivity between Sn(dmamp)2 and H2O plasma. These films had significantly high densities of 6.20–6.68 g·cm−3, which are noticeably superior when compared to those of the previously reported SnO2 films fabricated by ALD using different precursor/reactant combinations. The SnO2 films showed negligible impurity concentrations, irrespective of the deposition temperature. The polycrystalline structure of the SnO2 films was confirmed by X-ray diffraction and transmission electron microscopy measurements. These films, deposited at low temperatures of 60–90 °C, exhibited excellent electrical properties, i.e., high carrier concentrations of 3 × 1016−3 × 1018/cm3 and low resistivities of 4.20–57.2 Ω cm.

Influence of Sb inclusion on morphologies and carrier concentration properties of CTS thin films grown by sulfurization of Cu–Sn precursors

The impact of antimony (Sb) inclusion in Cu2SnS3 (CTS) films grown by sulfurization of Sb/Cu–Sn precursors and the growth mechanism of Sb-containing CTS were examined. The CTS grain size depended on the volume of the included Sb. During the sulfurization of the Cu–Sn precursor, S atoms first reacted with the Cu or Sn atoms and formed intermediate phases, such as CuS and SnS2. In addition, Sb acted to form a large-sized CuS grain during the low-temperature sulfurization up to 350 °C. The excess Sb tended to form Sb2S3 during the sulfurization, most of which disappeared from the upper layer of the CTS films due to re-evaporation. The carrier concentration of the Sb-included CTS tended to decrease from compensation with Cu vacancies. The experimental results obtained in this study may serve as a first step toward achieving the high-quality large grain CTS thin films and high-efficiency CTS solar cells.

Extended Compositional Range for the Synthesis of SWIR and LWIR Ge1–ySny Alloys and Device Structures via CVD of SnH4 and Ge3H8

A chemical vapor deposition (CVD) strategy is presented for the synthesis of Ge1–ySny alloys on Si wafers with band gaps in the short-wave infrared (SWIR) range of 1.8–2.6 μm, as well as in the long-wave infrared (LWIR) at 12 μm and beyond. This broad compositional versatility is achieved by CVD reactions of Ge3H8 and SnH4 as Ge and Sn precursors, respectively. The use of conventional SnH4 instead of the previously used SnD4 is found to be critical in synthesizing alloys with Sn contents between 30 and 36%, suggesting that at very low temperatures required to grow these supersaturated alloys, the incorporation of Sn is reaction-rate-dependent. The SnD4 precursor was historically preferred to SnH4 due to its longer lifetime at room temperature. However, the difference is found not to be significant from a practical perspective, and the fact that SnH4 can be synthesized from cheap and readily available starting materials represents a significant cost reduction and portends feasibility for commercial applications. The subtle differences between SnD4 and SnH4 that may explain why alloys with Sn incorporation higher than 30% can only be achieved with the latter are discussed in detail. Optical experiments indicate that such concentrations may be sufficient to cover much of the LWIR range. Device structures containing SWIR Ge1–ySny alloys were grown with the SnH4 precursor to demonstrate its suitability as a viable Sn source. The fabricated heterostructure pin diodes display excellent structural properties and a clear rectifying behavior, providing evidence that SnH4 is a practical and versatile CVD source of Sn at all concentrations of practical interest.

Low-temperature growth of crystalline Tin(II) monosulfide thin films by atomic layer deposition using a liquid divalent tin precursor

In this study, better-quality stoichiometric SnS thin films were prepared by atomic layer deposition (ALD) using a liquid divalent Sn precursor, N, N′-di-t-butyl-2-methylpropane-1,2-diamido tin(II) [Sn(dmpa)], and H2S. A relatively high growth per ALD cycle (GPC) value of approximately 0.13 nm/cycle was achieved at 125 °C. Furthermore, crystalline SnS films could be grown from room temperature (25 °C) to a high temperature of 250 °C. Density functional theory (DFT) calculations were used to examine the surface reactions and self-limiting nature of the Sn precursor. Mixed phases of cubic (π) and orthorhombic (o) SnS films were deposited at low temperatures (25–100 °C), whereas only the orthorhombic phase prevailed at high growth temperatures (>125 °C) based on the complementary results of X-ray diffractometry (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analyses. The optoelectronic properties of the SnS films were further evaluated by spectroscopic ellipsometry (SE) analysis. The results from the SE analysis supported the observed change from mixed π-SnS and o-SnS to o-SnS with increasing deposition temperature and allowed the determination of the energy bandgap (~1.1 eV) and a relatively broad semi-transparent window (up to 3000 nm). Overall, this new ALD process for obtaining a good quality SnS is applicable even at room temperature (25 °C), and we foresee that this process could be of considerable interest for emerging applications.

Effect of Sulfurization Time on the Physical Properties of Tin (II) Monosulfide Thin Films

Tin (II) monosulfide (SnS) films were prepared via sulfurization using sputtered Sn precursors of the tin metal layers in the presence of elemental sulfur vapor as a function of sulfurization time (ts) in the range of 30–180 min while keeping other parameters constant. The properties of these sulfurized layers were examined through suitable characterization techniques. The diffraction patterns exhibited various planes with the orientations (110), (120), (021), (101), (111), (211), (131), (210), (141), (002), (112), (122), and (042) corresponding to orthorhombic SnS at ts ≤ 90 min. However, for ts ≥ 120 min, the diffraction patterns showed a single (111) plane and enhanced the intensity of the peak with the increase of ts up to 150 min; with further increase of time, the peak intensity was found to decrease. The Raman spectra of films sulfurized at various ts showed modes at 95, 162, 189, 219, and 284 cm−1 for times were lower than 120 min and 95, 189, and 219 cm−1 for ts ≥ 120 min, related to SnS. In the transmittance spectra of the sulfurized films, it is clear that the film grown at ts = 30 min had higher transmittance, and with the increase of ts to 120 min, transmittance was decreased. For further extension of ts to 150 min, a sharp falling of the absorption edge was observed.