The maximum absorption of the ZnO nanoparticles samples annealed at 500°C and 700°C and shifted to higher wavelengths (Kulkarni et al., 2015). The band gap of the ZnO nanoparticles was calculated by extrapolating the curve drawn between (h ν) and (α hν) 2, Where ν is the frequency and α is the optical absorption coefficient. Band gap of zinc oxide nanoparticles is decreased when annealing temperature increases. This is because of the increase in the particle size of ZnO nanoparticles with annealing temperature (Kumar et al., 2013).
Figure 4.6 (b): Extrapolation curve for band gap determination of synthesized ZnO nanoparticles annealed at 8000 C and 9000 C
4.4. Electrical Properties (Four-probe technique)
The physical characteristic of the material is very important because of its use in everyday life. The electrical characteristic is one of the basic physical properties. The I-V characteristics of the ZnO NPs synthesized by a sol-gel method are measured by using a four-probe source meter. The I-V characteristics of the synthesized ZnO NPs annealed at different temperatures are measured for the electric resistivity measurement (Hamdelou et al., 2015). For all the samples of ZnO the electric current is a function of voltage as shown in (Figure 4.7). The current-voltage graph of all the samples of zinc oxide shows a straight line behaviour which means that the contacts made on zinc oxide (sample) are of ohmic. This straight-line region of all the samples of zinc oxide is a high resistance region. In the straight-line region, the electric current is dependent on voltage (Abdullah et al., 2017).
Figure 4.7: I-V characteristic of zinc oxide NPs annealed at different temperatures.
ZnO NPs are prepared by sol-gel method. Synthesized ZnO nanoparticles are studied by UV-Vis spectroscopy and strong peaks observed below 400 nm which indorses the formation of zinc oxide nanoparticles. The UV absorption peaks of zinc oxide nanoparticles have range from 300 to 800 nm. The structural properties of zinc oxide NPs are examined by XRD which indicates that the ZnO nanoparticles n are hexagonal structure with (hkl) planes of (100), (002), (101), (102), (110), (103), (112), (201) and (202) and diffraction angle of 2θ = 31.600, 34.270, 36.280, 47.410, 56.540, 62.770, 67.900, 69.000 and 76.790 respectively. The I-V characteristics of the ZnO NPs synthesized by a sol-gel method are measured by using a four-probe source meter. The I-V characteristics of the synthesized ZnO NPs annealed at different temperatures are measured for the electric resistivity measurement. The current-voltage graph of all the samples of zinc oxide shows a straight line behaviour which means that the contacts made on zinc oxide (sample) are of ohmic. This straight-line region of all the samples of zinc oxide is a high resistance region. In the straight-line region, the electric current is dependent on voltage. The SEM images shows that the ZnO NPs were a crack-free structure but when annealing temperature increases the morphologies of the zinc oxide nanoparticles were changed. ZnO NPs annealed at 500°C, 600°C and 700°C are rod-shaped and when calcined at 800°C, and 900°C turned into spherical shaped NPs with a size of around 400 nm.
Ab-initio study is a new technological advancement to examine major physical characteristics of solid. Such methods help us identify various physical characteristics of a substance which can reproduce the same results. Now it’s possible for us to show and check for such solid material properties that were not feasible for experimentation. An antipervoskite composition family of XNNi3 nitrides, where X belongs to the “d” block group, transitional metals and N belongs to the regular elements group.
The antipervoskite composition is identical to that of pervoskites. Most oxide compounds follow the antipervoskite configuration with the formula ‘ ABX3,’ These techniques help to identify a number of physical properties of a substance which can replace the same specialist where X’ are anions and A and B are cations, that represent the twelvefold coordinate’ A’ atoms, the middle part of atoms’ B’ cube in the junctions and’ X ‘ units in the middle of the cell can explain the cubic unit cells comprising’ A’ atoms. For antipervoskite programs, where the X and B’ element effects are replaced for their functions (Aleksandrov et al., 2004).
Most antiperovskites are known to distinguish from the perfect cubic shape, depending on pressure and temperature forming orthorhombic or tetragonal phases, close to the perovskite structure. It is not only the chemical composition, but the ionic radius of the constituent atoms as an equivalent size that defines whether compounds form an antiperovskite structure. The resistance element of Goldschmidt expresses this limitation. The tolerance factor must be from 0.71 to 1 for the structurally stable antiperovskite form. The orthorhombic or tetragonal crystal is between 0.71 and 0.9. From 0.9 to 1. It will be cubic. A significant type of material is Antiperovskite compounds because they show stimulating and useful physical properties not present in Perovskite materials. The ionic radii of the constituent atoms are not only the chemical composition but also the analog size in the antiperovskite family in the various instruments, inorganic compounds are integrated into the product range, materials, semi-conducting structures, insulators and superconductors. A major feature of antiperovskites is superconductor. Thermoelectrical, optical, mechanical & magnetic characteristics are reliant on on the electric characteristics of the material. The electrical and electronic industries have been associated with SnNNi3, CuNNi3, and MgNNi3 metals, all of these antipervoskite compounds XNNi3 play a vital role in the electronic industries. These have been refined and fabricated for almost as long as the metals. It was their unbeatable metallurgical properties that were responsible for their widespread applications for many years, especially electrical constants and various electrode systems (Aleksandrov et al., 1987).
Anti-perovskites are highly useful for data reading on hard disks, bio-sensors, microelectronic systems (MEMS) and other manufacturing equipment with magnetic field devices, such as GMR. Non perovskites are ideal materials under all weather conditions with their negative temperature resistivity coefficient. Over and above these applications, antiperovskite yield exceptional mechanical characteristics which cause their performance in car and room equipment possible because, in this field, they are used in other industrial applications as GMR, we needed considerable goods and a high mechanical power (Bannikov et al., 2010). Some of these XNNi3 contents have been commercially important for almost 20 years, while others appear to be in the development and research phase. The largest electronic devices are undoubtedly thick film resistors, thick film conductors, multi-layered ceramic capacitors (MLCCs) and connectors in terms of absolute metal application. First the majority of ruthenium is used and the others for most of copper. Connector manufacturing has been discussed extensively in this journal, where copper has been used as an expense-effective gold substitute. Thin film processing provides the largest variety of XNNi3 (X= Sn, Cu, Mg) uses. These occur from sensing to signaling and display in all areas of the technology and are often irreplaceable because these give rise to a simple response from specific devices. These are also widely used when electronic products are made. For instance, accurate temperature controls are carried out with platinum metal thermocouples on diffusion furnaces. High purity single crystals are made from molten materials which are non-contaminating and heat resistant, including lithium niobate, gadolinium-gallium grenets and yttrium aluminum grenets. Tubes made of platinum metals usually consists of gold, iridium or alloys according to the individual metal melting point are often the only suitable containers (Barberon et al., 1972).
Other mechanical properties in 12 MNNi3 compounds have recently been analyzed with (A = Zn, Mg, Cd, Al, Ga, In, Sb, Sn Pd, Cu, Ag, Pt). Of the six theoretical compounds which were predicted, only SnNNi3 and CuNNi3 were investigated-principles by (Kren et al., 1971). The average Voigt-Reuss-Hill (VRH) scheme performed theoretical calculations for materials SnNNi3, CuNNi3 and MgNNi3 by means of FP-LAPW (Full Potential-Linearized-Augmented Plane Wave) technique. In addition, many antiperovskites are good candidates for optical sensors due to the numerous electrical band gaps. Even though several physical characteristics have been recorded in the past, however, no detailed study has been available on the two-cell symmetry magnets of this essential compound group as far as we are aware which has motivated us to measure these qualities for the above described compounds, so that this theoretical lack can be overcome. It was therefore important to examine these compounds in order to make them easily available and efficient (Bannikov et al., 2010).
The study is constructed like fallows. In the next chapter No 2, the literature on the anti-pervoskites analysis is discussed. Chapter No 3 addresses the methods and techniques employed in the present work. The findings of Chapter No 4 are discussed, whereas the outcomes of the present work are addressed by Chapter No 5.