The Cu2SnS3 (CTS) thin fi lms were produced by deposition of Sn/Cu layers by RF sputtering follow... more The Cu2SnS3 (CTS) thin fi lms were produced by deposition of Sn/Cu layers by RF sputtering followed by annealing in an Ar/S atmosphere with S and Sn sources. According to XRD analysis and Raman spectroscopy, it was shown that single-phase CTS fi lms of a monoclinic structure with traces of the CuxS phase were formed at a temperature of 520oC. Scanning electron mic roscopy revealed a compact and homogeneous microstructure of the polycrystalline CTS layers. Photoluminescence spectra of the СTS films of monoclinic modification show one wide peak in the energy range of 0.7–1.0 eV, due to optical transitions of electrons from the conduction band to deep energy levels of acceptor-type defects.
Mo films deposited by DC sputtering are widely used as back contact in CIGS and CZTS based thin f... more Mo films deposited by DC sputtering are widely used as back contact in CIGS and CZTS based thin film solar cells. However, there have been only a few studies on the deposition of Mo films by RF sputtering method. In this context, Mo films on SLG substrates were prepared as a function of deposition pressure and power by using RF magnetron sputtering method to contribute to this shortcoming. Mo films were deposited at 250 0C substrate temperature by using 20, 15, 10 mTorr Ar pressures at 120 W RF power and 10 mTorr Ar pressure at 100 W RF power. Structural, morphological and reflectivity properties of RF- sputtered Mo films were clarified by XRD, AFM, FE-SEM and UVeVis measurements. In addition, due to sodium incorporation from SLG substrate to the absorber layer through Mo back contact layer is so essential in terms of improving the conversion efficiency values of CIGS and CZTS thin film solar cell devices, the effects of Na diffusion in the films were analyzed with SIMS depth profile. The electrical properties of the films such as mobility, carrier density and resistivity were determined by Hall Effect measurements. It was found that Mo films prepared at 120 W, 10 mtorr and 250 0C substrate temperature and then annealed at 500 0C for 30 min, had resistivity as low as 10-5 Ohm.cm, as well as higher amount of Na incorporation than other films.
We reported the growth of CZTSSe thin films on Mo-coated SLG substrates by the two-step approach ... more We reported the growth of CZTSSe thin films on Mo-coated SLG substrates by the two-step approach which includes the deposition of precursor films by the magnetron sputtering method at room temperature followed by selenization of the precursor films at 560∘C. Formation of CZTSSe films with the kesterite structure was confirmed by XRD and Raman spectroscopy analyses. The films are slightly Cu-rich and Zn-deficient. SEM study shown that the films have uniform surface morphology and densely packed structure without any voids and cracks.
A thin film solar cell device having the architecture Ni/Al/Al:ZnO/i-ZnO/CdS/CZTS/Mo/SLG with a R... more A thin film solar cell device having the architecture Ni/Al/Al:ZnO/i-ZnO/CdS/CZTS/Mo/SLG with a RF- sputtered CdS buffer layer was reported in this study. CZTS absorber layers were prepared on SLG and Mo-coated SLG substrates by sulphurization of sputtered stack precursor films. Structural, morphological, optical and electrical characteristics of absorber layer and interfaces of the layers in the cell structure were investigated in detail. It was determined that CZTS films were crystallized in kesterite structure and had a direct band gap of 1.4 eV and an absorbtion coefficient over 104 cm-1. A depth profile of the structure showed that the Na ions diffused quite deeply from SLG substrate through the Mo back contact layer into the CZTS absorber layer. The fabricated solar cell was characterized by current-voltage (I-V) measurements under simulated AM1.5 G spectrum at 0.1 W/cm2 illumination. An efficiency of 1.64% was obtained from the solar cell with an active area of 0.41 cm2. The open-circuit voltage (VOC), the short circuit current (ISC) and the fill factor (FF) values of the solar cell were 0.55V, 9.95mA and 0.37, respectively. The low FF value was attributed to high series resistance of the cell, the formation of MoS2 interfacial layer at Mo/CZTS interface and secondary phases in the absorber layer.
The Cu2SnS3 (CTS) thin fi lms were produced by deposition of Sn/Cu layers by RF sputtering follow... more The Cu2SnS3 (CTS) thin fi lms were produced by deposition of Sn/Cu layers by RF sputtering followed by annealing in an Ar/S atmosphere with S and Sn sources. According to XRD analysis and Raman spectroscopy, it was shown that single-phase CTS fi lms of a monoclinic structure with traces of the CuxS phase were formed at a temperature of 520oC. Scanning electron mic roscopy revealed a compact and homogeneous microstructure of the polycrystalline CTS layers. Photoluminescence spectra of the СTS films of monoclinic modification show one wide peak in the energy range of 0.7–1.0 eV, due to optical transitions of electrons from the conduction band to deep energy levels of acceptor-type defects.
Mo films deposited by DC sputtering are widely used as back contact in CIGS and CZTS based thin f... more Mo films deposited by DC sputtering are widely used as back contact in CIGS and CZTS based thin film solar cells. However, there have been only a few studies on the deposition of Mo films by RF sputtering method. In this context, Mo films on SLG substrates were prepared as a function of deposition pressure and power by using RF magnetron sputtering method to contribute to this shortcoming. Mo films were deposited at 250 0C substrate temperature by using 20, 15, 10 mTorr Ar pressures at 120 W RF power and 10 mTorr Ar pressure at 100 W RF power. Structural, morphological and reflectivity properties of RF- sputtered Mo films were clarified by XRD, AFM, FE-SEM and UVeVis measurements. In addition, due to sodium incorporation from SLG substrate to the absorber layer through Mo back contact layer is so essential in terms of improving the conversion efficiency values of CIGS and CZTS thin film solar cell devices, the effects of Na diffusion in the films were analyzed with SIMS depth profile. The electrical properties of the films such as mobility, carrier density and resistivity were determined by Hall Effect measurements. It was found that Mo films prepared at 120 W, 10 mtorr and 250 0C substrate temperature and then annealed at 500 0C for 30 min, had resistivity as low as 10-5 Ohm.cm, as well as higher amount of Na incorporation than other films.
We reported the growth of CZTSSe thin films on Mo-coated SLG substrates by the two-step approach ... more We reported the growth of CZTSSe thin films on Mo-coated SLG substrates by the two-step approach which includes the deposition of precursor films by the magnetron sputtering method at room temperature followed by selenization of the precursor films at 560∘C. Formation of CZTSSe films with the kesterite structure was confirmed by XRD and Raman spectroscopy analyses. The films are slightly Cu-rich and Zn-deficient. SEM study shown that the films have uniform surface morphology and densely packed structure without any voids and cracks.
A thin film solar cell device having the architecture Ni/Al/Al:ZnO/i-ZnO/CdS/CZTS/Mo/SLG with a R... more A thin film solar cell device having the architecture Ni/Al/Al:ZnO/i-ZnO/CdS/CZTS/Mo/SLG with a RF- sputtered CdS buffer layer was reported in this study. CZTS absorber layers were prepared on SLG and Mo-coated SLG substrates by sulphurization of sputtered stack precursor films. Structural, morphological, optical and electrical characteristics of absorber layer and interfaces of the layers in the cell structure were investigated in detail. It was determined that CZTS films were crystallized in kesterite structure and had a direct band gap of 1.4 eV and an absorbtion coefficient over 104 cm-1. A depth profile of the structure showed that the Na ions diffused quite deeply from SLG substrate through the Mo back contact layer into the CZTS absorber layer. The fabricated solar cell was characterized by current-voltage (I-V) measurements under simulated AM1.5 G spectrum at 0.1 W/cm2 illumination. An efficiency of 1.64% was obtained from the solar cell with an active area of 0.41 cm2. The open-circuit voltage (VOC), the short circuit current (ISC) and the fill factor (FF) values of the solar cell were 0.55V, 9.95mA and 0.37, respectively. The low FF value was attributed to high series resistance of the cell, the formation of MoS2 interfacial layer at Mo/CZTS interface and secondary phases in the absorber layer.
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Papers by E. Zaretskaya