Characterization Of CuInS2 Thin Films Research Articles

Characterization of CuInS2 thin films prepared from materials grown by using the mechanochemical method and their photovoltaic applications

Cu–In–S thin films were deposited on glass substrates using single-source thermal evaporation with ternary compounds as source materials. Polycrystalline CuInS2 powder grown using the mechanochemical method was employed as the source material. After deposition, the films were annealed in H2S gas at different temperatures from 250 to 500 °C for 60 min. X-ray diffraction patterns indicated that single-phase CuInS2 was formed when annealed above 400 °C. The grain size of the crystals in thin films was approximately 0.2 to 2.0 µm. The best Al/ZnO:Al/ZnO/CdS/CuInS2/Mo solar cell had an open-circuit voltage of 360 mV, a short-circuit current density of 18.6 mA/cm2, and a fill factor of 35.5%, resulting in 2.38% efficiency.

Characterization of CuInS2 thin films prepared by one-step electrodeposition

CuInS2 thin films were fabricated by one-step electrochemical deposition from a single alkaline aqueous solution and using conductive glass as the substrate. The electrolyte consisted in 0.01 mol L−1 CuCl2, 0.01 mol L−1 InCl3, 0.5 mol L−1 Na2SO3 and 0.2 mol L−1 Na3C3H5O(COO)3 (CitNa) at pH 8. The films were analyzed using a variety of techniques such as X-ray diffractometry, micro-Raman spectroscopy, X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy and photoelectrochemistry. After carrying out a thermal treatment in sulfur vapor, chalcopyrite CuInS2 thin films were obtained. Etching the films in KCN solution was found to be a key step, enabling a final adjustment in the stoichiometry. These thin films exhibited p-type semiconductor behavior with the bandgap of 1.43 eV. The results show that electrodeposition provides a cost-effective and versatile method for the preparation of thin films of CuInS2, even when acidic precursors need to be avoided.

Characterization of CuInS2 thin films prepared by chemical bath deposition and their implementation in a solar cell

CuInS2 thin films were formed by the sequential deposition of In2S3–CuS layers on glass substrates, by chemical bath deposition technique, and heating these multilayer 1h at 350°C and 400mPa. The morphology and thickness of the CuInS2 thin films were analysed by scanning electron microscopy, showing particles with elongated shape and length about 40nm, and thickness of 267 and 348nm for samples from 15 and 24h of deposition time in the chemical bath of In2S3, respectively. The energy band gap values of the films were around 1.4eV, whereas the electrical conductivity showed values from 64.91 to 4.11×10−3Ω−1cm−1 for the samples of 15 and 24h of In2S3 deposition bath, respectively. The obtained CuInS2 films showed appropriate values for their application as an absorbing layer in photovoltaic structures of the type: glass/SnO2:F/CdS/Sb2S3/CuInS2/PbS/C/Ag. The whole structure was obtained through chemical bath deposition technique. The solar cell corresponding to 15h of In2S3 deposition duration bath showed energy-conversion efficiency (η) of 0.53% with open circuit voltage (Voc) of 530mV, short circuit current density (Jsc) of 2.43mAcm−2, and fill factor (FF) of 0.41. In the case of the structure with 24h of deposition of In2S3 bath, η=0.43% was measured with the following parameters: Voc=330mV, Jsc=4.78mAcm−2 and FF=0.27.

Electrodeposition and Properties of CuInS<sub>2</sub> Thin Films

The preparation and characterization of CuInS2 thin films on ITO glass substrates prepared by one-step electrodeposition have been reported. Samples were characterized using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The results indicate that CuInS2 is the major phase for the film deposited at -1.0 V, after annealing at 550°C in sulfur atmosphere, and the sample is Cu-rich and p-type semiconductor. Additionally, the energy band gap and carrier concentration for the sample were found to be 1.43 eV and 4.20×1017 cm−3, respectively. Furthermore, the maximum photocurrent density of the sample was found to be -1.15 mA/cm2 under 255 lx illumination, the sample shows the photo-enhancement effect.

Characterization of CuInS2 thin films prepared by aerosol jet deposition

CuInS2 thin films were prepared using an aerosol jet deposition (AJD) technique with an aqueous solution of CuCl2, InCl3 and thiourea on a heated glass substrate. X-ray diffraction patterns showed that well-crystallized thin films with a preferential (112) orientation could be deposited at 400°C and [Cu]/[In] molar ratio of 1.2. Field emission scanning electron microscopy revealed well-crystallized grains in the films produced at high temperature of 400°C. In addition, energy dispersive X-ray spectroscopy confirmed that excess Cu and S were required to achieve well-crystallized CuInS2 films. As the [Cu]/[In] molar ratio increased from 0.8 to 1.4, the highest intensity of the (112) orientation and better crystallization were obtained at a [Cu]/[In] ratio of 1.2. The [Cu]/[In] ratios in the film were always higher than those in the precursor solution. All the CuInS2 thin films turned out to be p-type and had a band gap of 1.4eV. The depth profiles of Cu, In and S in the CuInS2 thin films deposited at the optimal [Cu]/[In] and [S]/[In] ratios of 1.2 and 3, respectively, were relatively constant throughout the films. Overall, the CuInS2 thin films deposited using the AJD method have well grown grains with good crystallinity.

Structural characterization of CuInS2 thin films from Cu–In metal inks

AbstractWe report the structural characterization of CuInS2 thin films based on Cu–In metal inks. CuInS2 films from the precursor films with different Cu/In ratios were sulfurized and investigated by SEM, XRD, Raman, and XPS. Morphological and compositional changes before and after etching of CuS impurity phase were also compared. By ex situ characterization of the CuInS2 films sulfurized at different temperatures, an established mechanism is proposed to explain the sulfurization process. The sulfurization is a diffusion‐limited process, in which the diffusion rate differences of Cu and In control the intermediate phases. Moreover, the Cu/In ratio and sulfurization temperature determine the morphological and structural qualities of the CuInS2 films.

Characterization of CuInS2 Thin Films with Different Cu/In Ratio

Thin films of CuInS2 were grown on glass substrate by successive ionic layer adsorption and reaction method with different [Cu]/[In] ratios and annealed at 400 °C for 30 min. The crystal structure and grain sizes of the thin films were characterized by X-ray diffraction method. Atomic force microscopy was used to determine surface morphology of the films. Optical and electrical properties of these films were investigated as a function of [Cu]/[In] ratios. The electrical resistivity of CuInS2 of thin films was determined using a direct current-two probe method in the temperature range of 300–470 K. It is observed that, the electrical resistivity values show a big decreasing with increasing [Cu]/[In] ratio. Hence, the [Cu]/[In] ratio in the solution can drastically affect the structural, electrical, and optical properties of thin films of CuInS2.

Characterization of CuInS2 thin films prepared by electrodeposition and sulfurization with photoluminescence spectroscopy

Abstract Potentiostatic electrodeposition and sulfurization techniques were used to prepare polycrystalline CuInS 2 thin films. X-ray diffraction and photoresponse measurements in a photoelectrochemical cell (PEC) revealed that photoactive polycrystalline CuInS 2 films can be deposited on Ti substrate. Photoluminescence (PL) spectroscopy was used to investigate the prepared thin films and optically characterize them. PL spectra revealed the defect structure of the samples with an acceptor energy level at 109 meV above the valance band and a donor energy level at 71 meV below the conduction band. The CuInS 2 thin films prepared in this investigation are observed to be In-rich material with n-type electrical conductivity.

Structural and optical characterization of CuInS2 thin films grown by vacuum evaporation method

Structural and optical properties of CuInS2 thin films grown by the single-source thermal evaporation method have been studied. The films were annealed from 100 to 500 °C after an evaporation in air. The surface morphology was investigated by scanning electron microscopy. The maximum grain size of the samples after annealing at 400 °C was over 500 nm. The EPM analysis concluded that the polycrystalline CuInS2 thin films after annealing below 100 °C were Cu-rich, and those annealed above 200 °C were In-rich. The bandgap energy of the CuInS2 films after annealing above 300 °C was about 1.48 eV.

Characterization of CuInS2 thin films for solar cells prepared by spray pyrolysis

We have made a study of the chemical composition, the electrical, the optical and the structural properties of polycrystalline CuInS2 thin films prepared by spray pyrolysis to be used for thin film solar cells. These films were deposited starting from aqueous solutions with different chemical compositions ([Cu]/[In] and [S]/[Cu] ratios) and at different substrate temperatures. In all cases, the material is p-type with grains preferentially oriented in the (112) direction of the sphalerite structure. The electro-optical properties show a very strong dependence on the [Cu]/[In] ratio in the solution. Films with copper excess have smaller resistivity and better crystallinity than those which are stoichiometric or have indium excess. The results obtained in this work show the possibility of having CuInS2 thin films with a wide range of resistivity, a fact that could be important for making solar cells based on this material.