Mechanochemically Synthesized CIGS Nanocrystalline Powder for Solar Cell Application

Copper Indium Gallium Diselenide (CIGS) is a compound semiconductor material from the group of I-III-VI. The material is a solid solution of copper, indium and selenium (CIS) and copper, gallium and selenium with an empirical formula of CuIn(1 – x)GaxSe2, where 0 x 1. CIGS has an exceptionally high absorption coefficient of more than 105 cm – 1 for 1.5 eV. Solar cells prepared from absorber layers of CIGS materials have shown an efficiency higher than 20 %. CuIn(1 – x)GaxSe2 (x 0.3) nanocrystalline compound was mechanochemically synthesized by high-energy milling in a planetary ball mill. The phase identification and crystallite size of milled powders at different time intervals were carried out by X-ray diffraction (XRD). The XRD analysis indicates chalcopyrite structure and the crystallite size of about 10 nm of high-energy milled CIGS powder after two and half hours of milling. An attempt for preparing the thin film from CIGS nanocrystalline powder was carried out using the flash evaporation technique. Scanning electron microscopy (SEM) reveals uniform distribution of CIGS particles in thin film. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3100

Effect of Rapid Thermal Annealing of CIGS Thin Film as an Absorber Layer

The influence of rapid post-deposition thermal annealing (500 °C for 2 minutes) on the CIGS thin films of different thicknesses (0.4 to 1.0 m) has been investigated. The deposition of CIGS is carried out using the flash evaporation at the substrate temperature of 250 °C. The as-grown and annealed CIGS is characterized by XRD, SEM, EDS, TEM, optical transmission, reflection, and electrical measurements. Lowering the thickness of CIGS absorber shows the remarkable influence on crystal structure, surface morphology, and composition of the overall film. Further improvement was observed by the rapid annealing process. Cu-rich composition was observed for annealed CIGS thin film having a thickness below 0.6 μm, while for 1.0 m thickness the composition is slightly Cu-poor and the compactly packed faceted grains observed. Optical band gap near to 1.05 eV and the electrical resistivity in the order of 104 Ωcm shows its future use as an absorber layer for CIGS solar cell. Furthermore, an attempt of making CIGS / CdS hetero-structure shows ideal behavior of the Schottky hetero-structure with the ideality factor of 1.5. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3100

Mechanochemically Synthesized CIGS Nanocrystalline Powder for Solar Cell Application

Copper Indium Gallium Diselenide (CIGS) is a compound semiconductor material from the group of I-III-VI. The material is a solid solution of copper, indium and selenium (CIS) and copper, gallium and selenium with an empirical formula of CuIn(1 – x)GaxSe2, where 0 x 1. CIGS has an exceptionally high absorption coefficient of more than 105 cm – 1 for 1.5 eV. Solar cells prepared from absorber layers of CIGS materials have shown an efficiency higher than 20 %. CuIn(1 – x)GaxSe2 (x 0.3) nanocrystalline compound was mechanochemically synthesized by high-energy milling in a planetary ball mill. The phase identification and crystallite size of milled powders at different time intervals were carried out by X-ray diffraction (XRD). The XRD analysis indicates chalcopyrite structure and the crystallite size of about 10 nm of high-energy milled CIGS powder after two and half hours of milling. An attempt for preparing the thin film from CIGS nanocrystalline powder was carried out using the flash evaporation technique. Scanning electron microscopy (SEM) reveals uniform distribution of CIGS particles in thin film. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3100

Nanostructured silver-graphite electrical contact materials processed by mechanical milling

281-287In last few decades there has been a growing interest in nanostructured materials in view of their improved mechanical, physical and chemical properties. A wide variety of techniques have been developed to synthesize nanopowders including high-energy milling or mechanical alloying (MA) for producing bulk nanostructures. High-energy milling is used for preparation of elemental and composite powders of different metals and non-metals. Literature reports the synthesis of ductile-ductile composites such as aluminium-graphite and copper-graphite by MA owing to its potential benefits in terms of improved mechanical properties. Reports are also there on the application of this technology for processing of silver-graphite contact materials offering improved switching properties. The present investigation deals with a comparative study on synthesis of silver-graphite nanocomposite powders in a planetary ball mill using two different approaches, namely milling of a blend of silver and graphite powder particles in one case and milling of only elemental silver powder in the other. The study revealed that somewhat inferior properties are obtained for the AgC bulk solids prepared from powders synthesized by the former approach. This is in view of the tendency of graphite to coat silver during milling, leading to very poor silver-silver interparticle contacts and resultant bulk solid with high porosity. However, an alternative approach of milling silver alone in the planetary mill is found to offer not only improved properties but also reduction in sintering temperature

Crystallite size estimation of elemental and composite silver nano-powders using XRD principles

157-161Studies on nanocrystalline materials require an accurate determination of crystallite size as well as the microstrains induced in the material. X-ray diffraction (XRD) and transmission electron microscopy (TEM) are the two well-known techniques for this purpose. Based on XRD principles, numerous approaches such as use of Scherrer equation, integral breath analysis, single-line approximation, Hall-Williamson method, etc have been developed for estimation of crystallite size. Present work deals with a systematic application of Hall-Williamson method for crystallite size estimation of high-energy milled elemental silver and silver-metal oxide (AgMeO) type composite powders and its comparison with Scherrer equation that does not take into account the peak broadening due to strain. The effect of second phase particles on the crystallite size of silver matrix in AgMeO composite is also investigated