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Spectroscopic ellipsometry Study of the Dielectric Function of Cu(In1–xGax)3Se5Bulk Compounds: Identification of Optical Transitions

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World Journal of Condensed Matter Physics 2017年第4期7卷 99-110页

作者： Dayane Habib georges el haj moussa Physics Department Faculty of Sciences IILebanese UniversityJdeidetLebanon Centre electronique et Micro-optoélectronique de Montpellier(CEM2) FacultéSciences et Techniques du LanguedocUniversitéde Montpellier IIMontpellierFrance

Using Spectroscopic ellipsometry (SE), the optical properties of Cu(In1−xGax)3Se5 bulk compounds, grown by the Bridgman method, were analyzed by varying x composition (0 ≤ x ≤ 1). Energy levels above the gap in the band scheme were determined by measuring the complex dielectric function ?at room-temperature for energies between 1.5 and 5.5 eV using a variable angle of incidence ellipsometer. The transitions values E1, E2 and E3 were observed above the gap for different samples of Cu(In1−xGax)3Se5 alloy. When a gallium atom replaces an indium atom, one assumes globally that the levels related to selenium and copper are unchanged. Conversely, the levels corresponding to the conduction band are shifted towards higher energies. Thus, the gap increases as the composition of gallium increases. Spectroscopic ellipsometry (SE) gave evidence for the interpretation of the choice of gap values which were compatible with that obtained from solar spectrum. Several other characterization methods like Energy Dispersive Spectrometry (EDS), hot point probe method, X-ray diffraction, Photoluminescence (PL), Optical response (Photoconductivity) were presented in this paper. The Cu(In1−xGax)3Se5 have an Ordered Vacancy Chalcopyrite-type structure with lattice constants varying as a function of the x composition. The band gap energy of Cu(In1−xGax)3Se5 compounds is found to vary from 1.23 eV to 1.85 eV as a function of x.

关键词： Chalcopyrite Photovoltaic Bulk materials Photoluminescence Optical Response X-Ray Diffraction Photoconductivity Spectroscopic ellipsometry

Identification of Optical Transitions by Spectroscopic ellipsometry (SE) on CuIn3Se5Bulk Compounds

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World Journal of Condensed Matter Physics 2017年第4期7卷 111-122页

Bulk materials were synthesized by the Bridgman technique using the elements Cu, In and Se. These samples were characterized by Energy Dispersive Spectrometry (EDS) to determine the elemental composition, as well as by X-ray diffraction for structure, hot point probe method for type of conductivity, Optical response (Photoconductivity) and Photoluminescence (PL) to determine the band gap value and Spectroscopic ellipsometry to find energy levels above the gap in the band scheme at room-temperature. They show a nearly perfect stoechiometry and present a p-type conductivity. CuIn3Se5 either has a Stannite structure, an Ordered Defect Chalcopyrite structure (ODC), or an Ordered Vacancy Chalcopyrite structure (OVC). The gap energy obtained for the different samples was 1.23 eV. Energy levels above the gap in the band scheme were determinate by measuring the dielectric function at room temperature for energies lying between 1.5 and 5.5 eV. Many transitions were observed above the gap for different samples. Spectroscopic ellipsometry gave evidence for the interpretation of the choice of gap values which were compatible with that obtained from solar spectrum.

关键词： Chalcopyrite Photovoltaic Bulk Materials Stannite Photoluminescence Optical Response X-Ray Diffraction Photoconductivity Spectroscopic ellipsometry

Fabrication, Characterization and Optical Properties of CuIn3Se5Bulk Compounds

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World Journal of Condensed Matter Physics 2015年第3期5卷 201-208页

作者： Dayane Habib Ouloum Aoudé Slyman Karishy georges el haj moussa Physics Department Faculty of Sciences II Lebanese University Jdeidet Lebanon Physics Department Faculty of Sciences IV Lebanese University Zahleh Lebanon Centre electronique et Micro-optoélectronique de Montpellier (CEM2) Faculté Sciences et Techniques du Languedoc Université de Montpellier II Montpellier France

The present work prepared the CuIn3Se5 ingots by using a horizontal Bridgman method and investigated the Energy Dispersive Spectrometry (EDS) and X-Ray Diffraction (XRD) to calculate the compositions of the ingots. Photoluminescence was used to check their optical properties. It was found that CuIn3Se5 had either a Stanite structure, an Ordered Defect Chalcopyrite (ODC) structure, or an Ordered Vacancy Chalcopyrite (OVC) structure. The gap energy obtained by Photoluminescence (PL) for the different samples is 1.23 eV. Studying the variation of the gap as a function of the temperature shows that the transition is a D-A type.

关键词： Chalcopyrite Photovoltaic Photoluminescence Optical Response X-Ray Diffraction

Influence of Iodine Pressure on the Growth of CuIn1-xGaxSe2Thin Films Obtained by Close-Spaced Vapor Transport “CSVT”

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World Journal of Condensed Matter Physics 2013年第4期3卷 164-168页

作者： Dayane Habib Roy Al Asmar Ziad el Helou georges el haj moussa Department of Physics Faculty of Sciences II Lebanese University Jdeidet Lebanon Department of Physics Faculty of Sciences II Lebanese University Jdeidet Lebanon Centre electronique et Micro-Opto- électronique de Montpellier (CEM2) Faculté Sciences et Techniques du Languedoc Université de Montpellier II Montpellier France

We present the results concerning photovoltaic materials CuIn1-xGaxSe2 thin films, which were obtained by close-spaced vapor transport “CSVT”. The influence of the iodine pressure on the growth of CuIn1-xGaxSe2 thin films was studied. The thin films were characterized by Energy Dispersive Spectrometry (EDS), Scanning electron Microscope (SEM), hot point probe method, X-Ray Diffraction (XRD), Photoluminescence, and Optical response (Photoconductivity). At high pressure, the deposition rate was very important. The films were relatively thick and homogeneous with large grains dimensions. These films are formed of crystals placed in a preferential orientation depending on the plan (112). At low pressure, the films were thin and inhomogeneous with relatively small grains. These films of crystals didn’t have preferential orientation.

关键词： Chemical Vapor Deposition CuIn1-xGaxSe2 Thin Films Chalcopyrite Photovoltaic