• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.305.2-305.2
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• 2016

Tin monosulfide (SnS) is one promising candidate absorber material which replace the current technology based on cadmium telluride (CdTe) and copper indium gallium sulfide selenide (CIGS) for its suitable optical band gap, high absorption coefficient, earth-abundant, non-toxic and cost-effective. During past years work, thin film solar cells based on SnS films had been improved to 4.36% certified efficiency. In this study, Tin monosul fide was obtained by atomic layer deposition (ALD) using the reaction of Tetrakis (dimethylamino) tin (TDMASn, [(CH3)2N]4Sn) and hydrogen sulfide (H2S) at low temperatures (100 to 200 oC). The direct optical band gap and strong optical absorption of SnS films were observed throughout the Ultraviolet visible spectroscopy (UV VIS), and the properties of SnS films were analyzed by sanning Electron Microscope (SEM) and X-Ray Diffraction (XRD).

• Journal of the Korean Electrochemical Society
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• v.18 no.1
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• pp.31-37
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• 2015

Composition-controlled ternary components chalcogenides germanium tin sulfide ($Sn_xGe_{1-x}S$) nanoparticles were synthesized by a novel gas-phase laser photolysis reaction of tetramethyl germanium, tetramethyl tin, and hydrogen sulfide mixture. Subsequent thermal annealing of as-grown amorphous nanoparticles produced the crystalline orthorhombic phase nanoparticles. All these composition-tuned nanoparticles showed excellent cycling performance of the lithium ion battery. The germanium sulfide nanoparticles exhibit a maximum capacity of 1200 mAh/g after 70 cycles. As the tin composition (x) increases, the capacity maintains better at the higher discharge/charge rate. This novel synthesis method of tin germanium sulfide nanoparticles is expected to contribute to expand their applications in high-performance energy conversion systems.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.2
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• pp.95-100
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• 2016

We fabricated a tin sulfide (SnS) layer with Sn/Mo/glass layers followed by a RTP (rapid thermal processing), and studied the film growth and structural characteristics as a function of annealing temperature and time. The elemental sulfur (S) was cracked thermally and applied to form SnS polycrystalline film out of the Sn percursor at pre-determined pressures in the RTP tube. The sulfurization was done at the temperature from $200^{\circ}C$ to $500^{\circ}C$ for a time period of 10 to 40 min. At ${\leq}300^{\circ}C$, 20 min., p-type SnS thin films was grown and showed the best composition of at.% of [S]/[Sn] $${\sim_=}$$ 1 and [111] preferred orientation as investigated from using XRD (X-ray diffraction) analysis and EDS (energy dispersive spectroscopy) and SEM (scanning electron microscopy), and optical absorption by a UV-VIS spectrometer. In this paper, we report the details of growth characteristics of single phase SnS thin film as a function of annealing temperature and time associated with the pressure and ambient gas in the RTP tube.

• Journal of Electrochemical Science and Technology
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• v.8 no.3
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• pp.206-214
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• 2017

SnS films have been prepared by electrodeposition technique onto Cu and ITO substrates using acidic solutions containing tin chloride and sodium thiosulfate with sodium citrate as an additive. The effects of sodium citrate on the electrochemical behavior of electrolyte bath containing tin chloride and sodium thiosulfate were investigated by cyclic voltammetry and chronoamperometry techniques. Deposited films were characterized by XRD, FTIR, SEM, optical, photoelectrochemical, and electrical measurements. XRD data showed that deposited SnS with sodium citrate on both substrates were polycrystalline with orthorhombic structures and preferential orientations along (111) directions. However, SnS films with sodium citrate on Cu substrate exhibited a good crystalline structure if compared with that deposited on ITO substrates. FTIR results confirmed the presence of SnS films at peaks 1384 and $560cm^{-1}$. SEM images revealed that SnS with sodium citrate on Cu substrate are well covered with a smooth and uniform surface morphology than deposited on ITO substrate. The direct band gap of the films is about 1.3 eV. p-type semiconductor conduction of SnS was confirmed by photoelectrochemical and Hall Effect measurements. Electrical properties of SnS films showed a low electrical resistivity of $30{\Omega}cm$, carrier concentration of $2.6{\times}10^{15}cm^{-3}$ and mobility of $80cm^2V^{-1}s^{-1}$.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.185-186
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• 2009

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.98.2-98.2
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• 2012

Thin film solar cells are growing up in the market due to their high efficiency and low cost. Especially CdTe and $CuInGaSe_2$ based solar cells are leading the other cells, but due to the limited percentage of the elements present in our earth's crust like Tellurium, Indium and Gallium, the price of the solar cells will increase rapidly. Copper Zinc Tin Sulfide (CZTS) and Copper Zinc Tin Selenide (CZTSe) semiconductor (having a kesterite crystal structure) are getting attention for its solar cell application as the absorber layer. CZTS and CZTSe have almost the same crystal structure with more environmentally friendly elements. Various authors have reported growth and characterization of CZTSe films and solar cells with efficiencies about 3.2% to 8.9%. In this study, a novel method to prepare CZTSe has been proposed based on selenization of stacked Copper Selenide ($Cu_2Se$), Tin Selenide ($SnSe_2$) and Zinc Selenide (Zinc Selenide) in six possible stacking combinations. Depositions were carried out through RF magnetron sputtering. Selenization of all the samples was performed in Close Space Sublimation (CSS) in vacuum at different temperatures for three minutes. Characterization of each sample has been performed in Field Emission SEM, XRD, Raman spectroscopy, EDS and Auger. In this study, the properties and results of $Cu_2ZnSnSe_4$ thin films grown by selenization will be presented.

• Current Photovoltaic Research
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• v.1 no.2
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• pp.109-114
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• 2013

$Cu_2ZnSnS_4$ (CZTS) nanoparticles were synthesized by a solvothermal method using copper (II) acetate, zinc acetate, tin chloride, and sulfur in diethylenetriamine solvent. Binary sulfide particles such as CuS, ZnS, SnS, and $SnS_2$ were obtained at $180^{\circ}C$; single-phase CZTS nanoparticles were obtained at $280^{\circ}C$. CZTS nanoparticles with spherical shape and grain size of 40 to 60 nm were obtained at $280^{\circ}C$. In the middle of 180 and $280^{\circ}C$, CZTS and ZnS phases were found. The time variation of reaction at $280^{\circ}C$ revealed that an amorphous state formed first instead of binary phases and then the amorphous phase was converted to crystalline CZTS state; it is different reaction path way from conventional solid-state reaction path of which binary phases react to form CZTS. CZTS films deposited and annealed from single-phase nanoparticles showed porous microstructure and poor adhesion. This indicates that a combination of CZTS and other flux phase is necessary to have a dense film for device fabrication.

• Current Photovoltaic Research
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• v.10 no.2
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• pp.33-38
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• 2022

Planner configuration thin film solar cells (TFSCs) with SnS/CdS heterojunction performed a lower short-circuit current (J_SC). In this study, we have demonstrated a path to overcome deficiency in J_SC by the incorporation of Se in the SnS absorber. We carried out the incorporation of Se in VTD grown SnS absorber by rapid thermal annealing (RTA). The diffusion of Se is mostly governed by RTA temperature (T_RTA), also it is observed that film structure changes from cube-like to plate-like structure with T_RTA. The maximum J_SC of 23.1 mA cm^-2 was observed for 400℃ with an open-circuit voltage (V_OC) of 0.140 V for the same temperature. The highest performance of 2.21% with J_SC of 18.6 mA cm^-2, V_OC of 0.290 V, and fill factor (FF) of 40.9% is observed for a T_RTA of 300℃. In the end, we compare the device performance of Se- incorporated SnS absorber with pristine SnS absorber material, increment in J_SC is approximately 80% while a loss in V_OC of about 20% has been observed.

• Journal of Electrochemical Science and Technology
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• v.9 no.4
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• pp.308-319
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• 2018

Single step electrodeposition of $Cu_2ZnSnS_4$ (CZTS) for solar cell applications was studied using an aqueous thiocyanate based electrolyte. The sodium thiocyanate complexing agent was found to decrease the difference in the deposition potential of the elements. X-ray diffraction analysis of the samples indicates the formation of kesterite phase CZTS. UV-vis studies reveal the band gap of the deposits to be in the range of 1.2 - 1.5 eV. The thickness of the deposit was found to decrease with increase in pH of the electrolyte. Nearly stoichiometric composition was obtained for CZTS films coated at pH 2 and 2.5. I-V characterization of the film with indium tin oxide (ITO) substrate in the presence and the absence of light source indicate that the resistance decrease significantly in the presence of light indicating suitability of the deposits for solar cell applications. Results of electrochemical impedance spectroscopic studies reveal that the cathodic process for sulfur reduction is the slowest among all the elements.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.389.1-389.1
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• 2016

The flexible solid state device has been widely studied as portable and wearable device applications such as display, sensor and curved circuits. A zero-bias operation without any external power consumption is a highly-demanding feature of semiconductor devices, including optical communication, environment monitoring and digital imaging applications. Moreover, the flexibility of device would give the degree of freedom of transparent electronics. Functional and transparent abrupt p/n junction device has been realized by combining of p-type NiO and n-type ZnO metal oxide semiconductors. The use of a plastic polyethylene terephthalate (PET) film substrate spontaneously allows the flexible feature of the devices. The functional design of p-NiO/n-ZnO metal oxide device provides a high rectifying ratio of 189 to ensure the quality junction quality. This all transparent metal oxide device can be operated without external power supply. The flexible p-NiO/n-ZnO device exhibit substantial photodetection performances of quick response time of $68{\mu}s$. We may suggest an efficient design scheme of flexible and functional metal oxide-based transparent electronics.