Investigation of CuIn1-xGaxSe2 thin films co-evaporated from two metal sources for photovoltaic solar cells

 CuIn1-xGaxSe2 (CIGS) thin films were grown by co-evaporation using two sources for the metal elements (Cu, Ga and In). A Mo coated soda lime glass substrates heated at 500 °C was used for the deposition. X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirm that these films are polycrystalline with a chalcopyrite structure and showed homogeneous grain size estimate about 25 nm. X-ray photoelectron spectroscopy (XPS) was performed to analyse the binding energy values of Ga3d and O1s onto CIGSe layers. The conductivity measurements in the temperature range of 40-400 K were carried out for 0.05≤ x ≤ 0.23. The effect of grain boundary scattering on the electrical transport played an important role in describing the transport processes in these films. The bowing factor is discussed taking into account the deposition techniques of CIGS films. It has been noticed that the open circuit voltage (Voc) is influenced by Ga content and the energy gap value of the absorber CIGS thin layers and yielded a poor efficiency of solar cells

Preparation and characterization of obliquely deposited copper oxide thin films

When a thin film is deposited by physical vapour deposition, with the vapour flux arriving at an oblique angle from the substrate normal, and under conditions of sufficiently limited adatom mobility to create a columnar microstructure, the resulting structure is somewhat porous and grows at an angle inclined toward the vapour source. This technique called glancing angle deposition was used in this work to grow nanocrystalline cuprous oxide thin films by annealing in air of copper films deposited firstly by this method onto glass substrates. The films were characterized for their structural, surface morphological, compositional; electrical and optical properties by using X-ray diffraction (XRD), scanning electron microscopy (SEM), electrical resistivity and optical (transmittance and reflectance) measurement techniques. It was found that the above properties were strongly dependent on the obliquely angle deposition. The nanocrystallite size in these films was varied by varying the obliquely angle deposition. Optical studies show a direct allowed transition around in the range 1.5–1.85 eV for the annealed films. An enhancement in the oxidation process was observed for high obliquely angles deposition

Study of Structural, Morphological and Optical Properties of Sb2S3 Thin Films Deposited by Oblique Angle Deposition

Sb2S3 thin films were deposited by thermal evaporation method with oblique angle deposition technique. During the deposition, the substrate temperature was maintained at Ts = 180 ◦C and the deposition angle was fixed at a = 0◦, 20◦, 40◦, 60◦, 70◦ and 85◦. X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM) and UV- Vis- NIR spectra were used to characterize the structural, surface morphology and optical properties respectively of the layers. X-ray diffraction spectra indicated that all the deposited Sb2S3 films are amorphous. The band gaps of the thin films were found to be direct allowed transitions and are around 1.87 eV. In addition it was found that the refractive index decreases from 2.98 for a = 0◦ to 2.28 for a = 85◦. The relationship between the flux incident angle a and the column angle b was also explored

Optical characterization of nano-structured Cu2ZnSnS4 thin films deposited by GLAD technique

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Impedance spectroscopy characterization of anisotropic nano-sculptured copper oxide Cu 2 O thin films for optoelectronic applications

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Effect of SnS addition on the morphological and optical properties of (SnS)m (Sb 2 S 3 )n nano-rods elaborated by glancing angle deposition

International audience(SnS)m(Sb2S3)n thin films were prepared by thermal evaporation using the glancing angle deposition technique (GLAD). The incident angle between the particle flux and the normal to the substrate was fixed at 80°. The Raman and XRD characterization revealed the amorphous character of the films due to the columnar structure as shown by the SEM characterization and AFM analysis. A strong change of the surface morphology of the films was observed and it depends on the composition. Optical properties were extracted from transmittance T and reflectance R spectra. (SnS)m(Sb2S3)n thin films exhibit high absorption coefficients (104–2 × 105 cm−1) in the visible range and the higher values were obtained for Sn3Sb2S6 and it has the highest photocurrent values. The direct band gap (Eg dir) was in the range 2.11–1.67 eV. The refractive indices are calculated from optical transmittance spectra of the films. The Sn3Sb2S6 sample exhibits a lower refractive index. All the dispersion curves of refractive index match well with the Cauchy dispersion formula and they were analyzed using Wemple-DiDomenico model. The Bruggeman effective medium approximation EMA was used to calculate the packing density of different compositions, and SnSb4S7 sample has the highest value. The so-called Verdet coefficient was evaluated from refractive index dispersion, and it was enhanced near the band gap

Linear and non linear optical properties of Sb<SUB>2</SUB>Se<SUB>3</SUB> thin films elaborated from nano-crystalline mechanically alloyed powder

International audienceSb2Se3 powder is achieved by mechanical milling of Sb and Se elements. X-ray diffraction analysis indicated the formation of Sb2Se3 orthorhombic phase. The latter finding is confirmed by both X-ray photoelectron spectroscopy characterization and Raman spectroscopy. Magnetic measurement revealed the ferromagnetic character of Sb2Se3 powder. Thin films were obtained by thermal deposition using Sb2Se3 powder as a precursor. Optical measurements carried out on thin films showed a high absorption coefficient and a direct band gap of 1.61 eV. The material has then potential application in photovoltaic conversion. Thin film refractive index dispersion ( n) obeys Cauchy dispersion equation. n is investigated and found to comply with Wemple-DiDomenico single oscillator dispersion model. The energy E 0 of the oscillator and E d dispersion energy are derived from the refractive index investigation. Spitzer-Fan model exploitation was allowed to derive the high-frequency dielectric constant ɛ ∞ and the carrier density N/ m* ratio. Additionally, Verdet constant V is determined based on the refractive index dispersion study. Furthermore, the nonlinear susceptibility χ (3) as well as nonlinear refractive index are determined for Sb2Se3 thin films. The nanostructure of the material is likely responsible not only for the high nonlinear characteristics but also for the low magnetic character in Sb2Se3

Structural, Morphological and Optical Properties of Sn3Sb2S6 Thin Films Synthesized by Oblique Angle Deposition

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