physical properties of ternary semiconductors and few alloys

Abstract: The world of physics has been completing hundreds of years in applying scientific methodologies to understand basic principles of nature, matter and energy and how they interact. A Physicist conducts research within one area of physics through interaction with many other disciplines. There are many subjects of physics from very small particle physics to very large cosmology or study of the Universe. In these vast areas of subjects Semiconductor technology plays a vital role. The optical and related properties of few II-VI semiconductors are studied in the design and analysis of Opto-electronic devices. Various analytical expressions were developed to study the optical constants of refractive index, band energy gap, and absorption coefficient. These are used to evaluate variation of refractive index with pressure (dn/dp) and effective mass of charge carriers in ternary semiconductors and comparison of the results is made with available reported values.

INTRODUCTION: Materials can be categorised in to conductors, semiconductors and insulators by their ability to conduct electricity. Semiconductors have resistivity between 10-4 OBJECTIVES: The main objectives of the research are: - 1) Determination of Variation of refractive index with pressure (dn/dp), effective mass of charge carriers (m*), Polarizability (aM), width of energy gap (Eg) of Group II-VI, Group III-V ternary alloys 2) The physical studies of Group II-VI and Group III-V are studied in literature survey. 3) The dispersion data of these ternary compounds are used to evaluate nµ, which is major component of dielectric polarization is used to evaluate band energy gap and compared the data on Eg with reported values and then by stressing the importance of dispersion data. 4) The optical polarizability (aM) of Group III-V and Group II-VI ternary systems are evaluated from data of refractive indices at various wavelengths by a new dispersion relation by taking the slopes of curves 1/l2 and 1/n-1. These values are used to evaluate diamagnetic susceptibility (cM), molecular electron ionization cross section (Q). 5) The optical energy gap values at various compositions (x) of ternary alloy systems were evaluated from the plots of Öahn versus hn. By using a, the optical energy gaps of few ternary semiconductors are estimated by using (ahn) ½ versus (hn)

METHODOLOGY: Characterization of Semiconductors is very important as a x of a constituent in the Semiconductors is going to have significant changes for Eg. CdSxSe1-x, the Y of Sulphur is going to play much role in electronic distribution and reflect in physical properties also the properties like reflectivity which is an important parameter in the calculation of anti reflecting properties of mirrors in labels is significant, thus the detailed study of physical properties like polarizability, susceptibility. Electron ionisation cross-section and absorption coefficients are taken up. The energy gap, a parameter of at most important in calculating Electrical Optical and Electro Optical properties is also stress. The variation of the physical properties with the % of the constituent leading to additive nature, non-linear contributions if any are also to be discussed. The secondary data has been collected from various published journals

HYPOTHESIS: The Linear variation or the presence of nonlinear increments in the Physical property with the change in value of x, the % of the constituents is also a factor to reckon with the presence of non linear contributions if any are likely to through light on non linear phenomena in Optical effects.

CONCLUSION: Growth and characterization of semiconductor films have thrown much of useful information on their applicability in the design of solar cells, antireflective films etc. The mobility of the electrons and holes in semiconductor are governed by the concentration of the dopants. Optical Studies, Magnetic Studies and Allied Electrical Studies of these compounds are gaining importance. The change of optical properties with thickness of film brings new aspects of understanding between electron donors and acceptors. This is a pre requisite for better understanding of mechanism of the growth and analysis of Nana crystals. Thus it is aimed in the present investigation to have a thorough study of physical properties of this ternary systems and extending this concept to Nana Scales. References: [1] Journal of Alloys and compounds 218 PrasadaRao, K.Hussan, O.M Reddy, K.T.R., Reddy. [2] Gosh, D.K., Samantha, L.K and Bhav, G.C., Pramaha, 23(4), 485 [3] Nagabhushan Rao, K. , Ph.D. Thesis, “Optical studies in semiconductors” S.K.University, Ananthapur, India PP224 (1987) [4] Ghosh, DK Samantha, L.K and Dhar, G.C, Pramana, 23(4) [5] Khawaja, E. and Tornlin, S.G.J.Phys. D: Applied Physis, 8581 [6] Sadao Adach and Toshifumi Kimura, Jph.J.Applied Physics, 32 [7] Sathyalatha, K.C., Uthana.S. And Reddy P.J.Thin Solid Films: 74 [8] Hand Book of Optical Constants of Solids, Edward Palik. [9] Srob, L and Marfaing Y., Solid state community 58, 343 [10] Murthy Y.S. Naidu, B.S. and Reddy P.J., Materials Science and Engineering, B8,175 [11] Heavens, O.S.,” Optical Properties of thin Solid Films” [12] Rurton, L.C and Hench, TL Applied Physics Letters., 29.612 [13] Smith L J Applied Physics 46, 2336 [14] Roneo, N Sberveglleri G. And Terri cone, L. Thin Solid Films 64.21 [15] Prasada Rao, K. Hussein , DM Reddy, KTR.,Reddy P.S, Uthanna, S.Naidu, B.S and Reddy, P.J.Journal of Alloys and compounds 218,86 –89 [16] Hemachandra G, Hussain O.M, Uthana.S and Naidu, B.SJ.Materols science Letters.,20 [17] Jain S.C.Sharma, T.P and Arora N.D.Journal of Physics and Chemistry of Solids. [18] AL Kumari, S.A.Tulbah, Z., Almarshed, A.AL Harld, F. and AL Moneef, M.Indian Journal of pure and Applied Physics 58, [19] Hill R and Casperd A.N,. Solid State community 17.3351 [20] Ellis S.G., J.Physics and Chemistry of Solids 29,1139.

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