G. 4000m with the help of a special

G. Kanellis, K. Kampas (1997) the artificial plane calculates and on serve the phenomenon of reflectance which separates only single crystals of AgGaTe2 and AgGaSe2 ranging from 100m to 4000m with the help of a special instrument naming Michelson interferometer for the relation energy perpendicular to speed of light and energy parallel to speed of light .The conclusions were made by the procedures through Lorentz and Kramer’s Kroning.  By equating the measured frequencies of the materials of AgGaS2 .To the frequencies observed by diatomic linear chain model that tells or explain us that the vibrations of 1-VI ions of the second b2 mode can be assigned which are in phase which are opposite in direction to the III ions which were at rest.

J ?a?zewski and K Parlinski (1999) for two chalcopyrite crystals AgGaTe2 and AgGaSe2 which were observed by hallmann-feymann forces which are nearly equal to the local density by the density functional theory .with the help  of this exact technique the phonons are arranged at high correspondence points of the chalcopyrite structure which have been measured by this method  .the conclusion of this technique were in good favor with the date which was conducted through experiments by Raman, inelastic neutrons and infrared scattering

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A. Chahed et al., (2005) with the help of local density approximation which works with the full potential linearized plane wave procedure we can examine the optical, electronic and structural  characteristics of two chalcopyrite crystal naming  AgGaSe2 and AgGaS2 .The study of unit cell (bulk modulus, internal parameter  and c=a ratio )with the help of geometric optimization resembles with the data which we collect through experiments .for both the chalcopyrite materials (AgGaS2 and AgGaSe2) the energy gap is seen to be target and the state of the gaps depended upon the mode through which Ag 4d and Ga 3g electrons are considered to be center or valence state. The conclusion of density of states, charge density distribution and on band structure are shown. Also the optical characteristics of our conclusions on refractive index n and complex direct functions of AgGaSe2 and AgGaS2 crystals are described by us. We have examine the structure of the dielectric functions, which were also found in the studied energy region

H. Neumann (2007) By direct phonon method and first principle calculation , the characteristics like isotropic and anisotropic temperature parameters and heat capacities which are thermodynamically just like characteristics of Debye temperature of CuInS2 CuInSe2,AgGaS2,AgGaSe2 ,AgGaTe2 and ZnSnP2chalcopyrite compound that have been measured in harmonic approximation which depends upon the temperature . The result which were calculated through this method were similar to the data that was made through experiments with the help of literature .By equating the heat capacities which are calculated at constant pressure to the heat capacities that are measured at constant  volumes , harmonic approximation applicability was estimated by temperature range.

A.V. Kopytv (2008) In chalcopyrite structure with phonons spectra of AglnSe2 and AglnTe2 are calculated by linear response method and using Raman and IR spectroscopy to calculated the frequencies at the middle of brillouin zonein experimental data The spiritual of the AglnTe2 and AglnSe2 crystal display trio bands according to the atomic shall to the vibrational mode. The vibration in the low and median frequency are mixed and closed to identical contributions of all sublattices and the higherfrequencies are connected with the share of ln, CVI and Ag,CVI (CVI = Se, Te) atoms .Ag-CVI bonding are weaker as compared to ln-CVI bonding and these bond permit us to do the inference that in the crystal under investigation.

Anek Charoenphakdee et al., (2009) by solid-state reaction of Ag2Te, Ge2Te3and In2Te3 synthetized AgGaTe2, AgGa5Te8, AgInTe and AgIn5Te k and prepared by High Density polycrystalline pallets. Thermal conductivity k in the range of 25?c to 597?c were observed by the application of laser flash method .the thermal conductivity k values of AgGa5Te8, AgGaTe2, AgIn5Te8 and AgInTe2 were 0.52, 1.94, 1.08 and 2.04 Wm-1k-1 respectively. Debye temperature and crystal structure with magnitude relation of thermal conductivity k were studied

Wentao et al., (2012) described the thermoelectric and optical properties of p-type doped AgGaTe2 chalcopyrite structure have been study with in DFT theoretical work. The electrical movement of AgGaTe2 highly depend on the doping level and depend upon the temperature. The Seebeck coefficients at different temperatures similar to the optimal doping level are all about 270µV/K. Thus, the optimal doped AgGaTe2 could be get by set the Seebeck coefficient to 270µV/K in the experiment. The experiment show that AgGaTe2 at 900 K reaches 1.19 under optimal doping level showed AgGaTe2 is a very bright thermoelectric material.

David Parker and David J. Singh (2012) the p-type AgGaTe2 potential thermoelectric performance which was analyzed by us has already been displayed a ZT of 0.8 with partial improvement and the band structure properties are measured by this are same just like the combination of light band and heavy band isotropic movement, which results in the better efficiency which include in several tri-chalcopyrite structure semiconductors. In order to improve the efficiency of AgGaTe2 by us at hole concentration ranging from 4 1019 and 2 ×1020cm-3 at 627?c and 2 ×1019 and 1020cm-3 at 427?c come other chalcopyrite semiconductor at similar doping and temperature might represent good thermoelectric performance if they are not used for higher lattice thermal conductivity

H.peng et al.,(2014) determined the electronic structure and thermoelectric shipping properties of AgGaTe2 measured by DFT and Boltzmann transport theory.The electronic band structure conduct in a clear-cut decoupling effect of the degenerate band due to the spin–orbit coupling. The improvement of the power factor of AgGaTe2 can be showed by optimizing the carrier concentration and the utilization of the anisotropy.

 

Saeed Ullah et al., (2014) we study for the trio semiconductor compounds AgXY2 (X=Al,G,ln) and (Y= S,Te,Se) by using (DFT) which depend on the (FP-LAPW) method in heusler and Chalcopyrite crystal phases. In chalcopyrite phase, we measure the band gap and lattice constant for (AgXY2) are best agreement with useable experiment data. By using technique (MBJ) method which are better experimental result and also better band gap as compared to others by using (GGA)and EV-GGA) method. By following Columns in periodic table, we can see that decrease   band gap in cation .Charge density plots and quantified with the help of Bader’s analysis to produce chemical bonding trends. In the visible and ultraviolet (uv) regions are favorable for optoelectronic devices.

 

Jianhui Yang et al .,(2017) explained the vibrational, electronic and thermoelectric transport

Properties of AgInTe2 and AgGaTe2 with chalcopyrite structure have been studied. The electronic structures are solved by DFT within the (GGA) of Perdew–Burke–Ernzerhof functional considering the Hubbard-U exchange correlation. The band-gaps of AgInTe2 and AgGaTe2 are more than higher as compared to general GGA functional results and agree well with the present experimental data. The effective mass of the hole and the shape of density of states close the border of the valence band, which showed AgInTe2 and AgGaTe2,are let p-type thermoelectric materials. In this article, the lattice dynamics shows the low thermal conductivities of AgInTe2 and AgGaTe2. The thermoelectric transport propertiesdepend upon their carrier concentration for p-type AgInTe2and AgGaTe2in a large range of temperatures has been focused in detail. The results display that p-type AgInTe2 and AgGaTe2at 800K can score the merit values of 0.91 and 1.38 at about 2.12×1020 cm?3 and 1.97×1020cm?3carrier concentrations, respectively. This result confirmed that p-type AgGaTe2 is a potential thermoelectric material at high temperature.

 

 H. J. HOU et al.,(2017) By the application of DFT (Density functional theory), for the AgAlS2 structure lattice constants, elastic constants and bulk modulus parameters are measured .these parameters are observed with excellent theoretical and experimental results . Different parameters as if shear modulus (G), young’s modulus, bulk modulus and wave velocity of the chalcopyrite structure observed first time .In the range of o to 10GPa pressure and 727?c temp equation of state of chalcopyrite structure was observed.

V Kumar* and B P Singh (2017) With the help of DFT, we can measure the structural and elastic features of AIBIIIC2vI through plane wave pseudo –potential method. (Eg) energy Gap ,(DOS) Density of states, Lattice constants (a and c), tetragonal distortion (?) and bond lengths of the A–C (dAC), internal parameter (µ) , and B–C (dBC) bonds in AIBIIIC2vIhave been measured. The values of (Cij) elastic constants, (B) bulk modulus, (Y) Young’s modulus,

(G)  Shear modulus, (t) Poisson’s ratio, (A) Zener anisotropy factor, (HD) Debye temperature and G/B ratio have also been calculated. The value of 8 parameters of 20 compounds of AIBIIIC2vI family and 15 parameters of CuTIS2 and CuTIS2 except AgInSe2 and AgInS2 have also measured for the first time. So the available measured, reported and available experimental values have been reasonably good proposal was obtained