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In this work, copper indium gallium selenide (CIGS) thin films were prepared by sputtering CIGS quaternary target and subsequent annealing in the 450–550 °C range. For analyses purpose, the films were peeled off from Mo-coated glass and both parts were named as ‘CIGS side’ and ‘Mo side’ respectively. Raman spectroscopy and X-Ray Photoelectron Spectroscopy (XPS) were performed to identify crystalline phases and chemical compositions. On the ‘Mo side’, a MoSe x layer was evidenced with increased thickness for higher annealing temperature. On the ‘CIGS side’, XPS highlighted a continuous Ga enrichment and a Cu content decrease with increasing temperature. Na was detected on both Mo and CIGS sides. Its concentration and distribution relied on the temperature. Finally, relationships between interface modifications and annealing temperature were discussed . [ABSTRACT FROM AUTHOR]

Abstract: In this work, bilayer ZnS/CdS film was prepared as an improved window layer of CdTe solar cell. TEM was used to observe the cross section of the bilayer structure. The total thickness of ZnS/CdS film was about 60nm, which could allow more photons to pass through it and contribute to the photocurrent. Optical properties of the bilayers were investigated using UV–vis spectroscopy. Compared with poor transmission of standard CdS film in the short wavelength range of 350–550nm, the transmission of ZnS/CdS was improved and reached above 50%. The ZnS/CdS was annealed with CdCl2. X-ray photoelectron spectroscopy (XPS) was used to investigate its chemical properties. A possible diffusion between CdS and ZnS was observed after annealing. The efficiency of standard CdS/CdTe solar cell was 9.53%. The device based on ZnS/CdS window layer had a poor 6% efficiency. With annealing treatment on ZnS/CdS layer, the performance was improved and reached 10.3%. In addition, the homogeneity of solar cell performance was improved using ZnS/CdS window layer. A thin ZnS layer was quite effective to reduce the possible shunt paths and short parts of window layer and consequently contributed to fabrication of a homogeneous CdTe solar cell. [Copyright &y& Elsevier]

We report a study of copper indium gallium selenide (CIGS) thin film growth in the annealing process at temperature range from 120°C to 600°C. Thin films were prepared by sputtering metal precursors and subsequent selenization process. Surface morphologies of thin films were observed by using high resolution field emission scanning electron microscopy (FESEM). Phases in quaternary systems Cu–In–Ga–Se were investigated by X-ray diffraction (XRD). Evolution of crystalline structure in the film surface was studied by Raman spectra. A possible reaction path from metallic precursors to a single CIGS phase was obtained by merging all results of SEM, XRD and Raman. Above 210°C, selenium reacted with Cu and In to form binary selenide. CuSe crystalline platelets were observed clearly in the film surfaces. When temperature was reaching 380°C, Cu2−x Se and InSe reacted with excess Se to form CuInSe2 (CIS) and contributed to the grain growth. Above 410°C, Ga-rich phase was detected in the films. With increased temperature, Ga diffused into CIS crystalline lattices. Finally, at 600°C, a single phase of Cu‐In‐Ga‐Se quaternary system was formed. A large number of triangular and hexagonal structures were observed in the film due to a re-crystalline process at a high annealing temperature. [ABSTRACT FROM AUTHOR]

Abstract: CdS layers grown by chemical bath deposition (CBD) are treated in different ways to improve the performance of CdS/CdTe solar cells. It has been found that the open circuit voltage of the CdS/CdTe solar cell increases when the CBD CdS is annealed with CdCl2 before the deposition of CdTe by close spaced sublimation (CSS). A thin CBD CdS (∼80nm) with bi-layer structure can significantly improve the short circuit current of the CdS/CdTe solar cells. [ABSTRACT FROM AUTHOR]

Abstract: CdS layers grown by chemical bath deposition (CBD) are annealed in the oxygen and argon–hydrogen atmosphere respectively. It has been found that the open circuit voltage of the CdS/CdTe solar cell increases when the CBD CdS is annealed with oxygen before the deposition of CdTe by close spaced sublimation (CSS), while the performance of the solar cell decreases when the CBD CdS is annealed with argon–hydrogen. Electronic properties of the CdS films are investigated using X-ray photo-electron spectroscopy (XPS), which indicates that the Fermi level is shifting closer to the conduction band after annealing in the oxygen and consequently a higher open circuit voltage of the solar cell can be obtained. [ABSTRACT FROM AUTHOR]

Copper indium gallium selenide (Cu(In,Ga)Se 2 , CIGS) absorbers have been prepared by sputtering a CIGS quaternary target and imposing a subsequent annealing process. The influences of annealing temperatures on the morphology, chemical composition, microstructure and electronic properties as well as phase transformations have been investigated. Scanning Electron Microscope (SEM), X-Ray Fluorescence (XRF), Energy-dispersive X-Ray spectroscopy (EDX), X-Ray Diffraction (XRD), Raman spectroscopy and Hall analysis have been employed to analyze the morphology, chemical composition, microstructure and electronic properties, respectively. The results show that a phase separation process occurs in the CIGS absorbers when the as-deposited CIGS samples are annealed at the temperatures between 210 and 380 °C. The surfaces are partly covered by regular shaped grains and platelets, which are corresponding to Cu–Se phases. When the absorbers are annealed at the temperature higher than 410 °C, the CIGS absorbers recrystallize. This process improves the grains size and makes the absorbers become homogeneous and compact. Hall analysis shows the variation of electronic properties with the increase of annealing temperatures. The relationships between the electronic properties and the microstructure have been discussed in the paper as well. The solar cells have been fabricated with an optimized annealing temperature of 550 °C. The highest efficiency of the CIGS solar cell devices reaches 13.5%. [ABSTRACT FROM AUTHOR]