Dr. M. Venkata Ramana, Department of Physics, S.R.& B.G.N.R.Government Arts and Science College, A.P, India
E-mail: mvr1508@gmail.com

Dr. Ahmed Hashim Mohaisen Al-Yasari, Department of Physics, College of Education For Pure Science, University of Babylon, Hilla, IRAQ
E-mail: ahmed_taay@yahoo.com

Dr. Abdel Fattah Mohammed Mansour, Solid State Electronics Lab., Solid State Physics Department, Physics Division, National Research Center (NRC), Egypt
Email: amamansour@gmail.com