Study of Crystal Structure Profile Fitting of CuO for different Intensities of Gamma Radiation using Rietveld Refinement Method
Abstract
The study of crystal structure profile fitting described by Hugo Rietveld named Rietveld Refinement became popular for profile fitting and microstructural analysis. The Rietveld method refines user-selected parameters to minimize the difference between an experimental parameter (observed data) and a model based on the hypothesized crystal structure and instrumental parameters (calculated data). In this paper, profile fitting of CuO has been discussed for different intensities of XRD data. Here Goodness of fitting is kept 1-2. For different dose the goodness of fitting changes.
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Introduction
1.1 Cupric Oxide (CuO)
During the past few years, the nano-semiconductors have proved itself beside the bulk semiconductors and have attracted extensive attention from scientists not only for the dramatic changing of their properties as a function of size, which is so significant for fundamental research, but also for their applications in different topics of technology as nano-electronics, photonics, optoelectronics, nano- medicine and nano-devices of renewable energy. It is well recognized that metal oxides have reached an important place in several areas of chemistry, physics and materials science. Currently, copper oxides, especially found a wide application domain in catalytic, field emissions, gas sensing, lithium batteries, and solar cells [2–6].
Metal oxide semiconductor thin films have been studied for their use in optoelectronic and photonics technology. Among the metal oxides, copper oxide (CuO) is a p-type semiconducting oxide material. CuO exhibits superior properties, including a direct band gap (~ 1.2 eV-2.1 eV), non-toxic nature, excellent chemical stability, cost effective synthesis, abundance in nature and reasonably good electrical properties [7-9]. CuO has received considerable attention for various applications, including gas sensors, biosensors, solar cells, batteries, magnetic storage materials, catalysts, diodes and transistors [8-12].
Interaction of radiant energy with matter, especially y−radiation, is an enormously important from the view point of theory and practice. Gamma irradiation, the high energetic form of electromagnetic wave, causes two effects when interacting with materials: first, ionization which creates secondary reactions with ejected electrons and second, the atomic displacement which defects into atomic lattice. Irradiation of solids with high energy radiation, like y- rays, electrons or neutrons expected to affect their optical, electrical and physical properties. The various researches illustrate that when solid state materials are exposed to ionizing radiation, their microstructural properties are altered. Numerous efforts have recently been made to investigate the influence of gamma radiation on different metal oxides and polymers. Copper Oxide is a group II-VI semiconductor with optical properties. It exhibits a wide variety of morphologies in the nano regime that can be grown by tuning the growth habit of the CuO crystal. There are two stable crystalline phases of the Copper oxide such as Cupric oxide (CuO) or tenorite and Cuprous oxide (Cu2O) or cuprite.
Conclusion
Materials are essential to our technological society: Semiconductors in the electronic industry, zeolites as catalysts in the petrochemical industry, ceramics in medicine and engineering and possibly in the future, high –temperature superconductors in electrical engineering.
In order to understand the properties of these materials and to improve them, the
Atomic structure has to be known. An effective way to do this is by means of diffraction techniques using neutrons from nuclear reactors and particle accelerators or X-rays from X-ray tubes and synchrotrons. The Single crystal diffraction technique using relatively large crystal of the material, gives a set of separate data from which the structure can be obtained.
However, most materials of technical interest cannot grow large crystals, so one has to resort to the powder diffraction technique using material in the form of very small crystallites. The drawback of this conventional powder method is that the diffraction peaks grossly overlap, thereby preventing proper determination of the structure. The” Rietveld Method” creates a virtual separation of these overlapping peaks, thereby allowing an accurate determination of the structure .The method has been so successful that nowadays the structure of materials, in the form of powders, is routinely being determined, nearly as accurately as the results obtained by single crystal diffraction techniques. An even more widely used application of the method is in determining the components of chemical mixtures. This quantitative phase analysis is now routinely used in industries ranging from cement factories to the oil industry.