[1] Ibn Zohr Univ, Fac Sci, Equipe Semicond Nanotechnol & Programmat Sci, Res Grp,Phys Dept, BP 8106, Hay Dakhla 80000, Agadir, Morocco
[2] Sungkyunkwan Univ, Sch Elect & Elect Engn, Suwon 440746, South Korea
[3] Natl Taiwan Univ, Dept Phys, Taipei, Taiwan
[4] Univ Hassan II Mohammedia Casablanca, Fac Sci & Techn Mohammedia, EEA TI, Casablanca, Morocco