FIZIKA A 17 (2008) 1 , 15-28
CRYSTAL STRUCTURE AND OPTICAL PROPERTIES OF QUATERNARY SYSTEMS OF Bi-Sb-Te-Se
A. M. ABOU EL SOUDa, B. S. FARAGa, I. S. AHMED FARAGa,
S. A. GADa and H. A. ZAYEDb
aSolid State Physics Laboratory, National Research Centre, Dokki, Cairo, Egypt
bPhysics Department, Girls College for Art, Science and Education, Shams University, Cairo, Egypt
Received 4 May 2005; Revised manuscript received 14 June 2006
Accepted 24 January 2007 Online 25 September 2008
The quaternary systems of Bi-Sb-Te-Se were synthesized by direct fusion
technique. Thin films of these compounds were prepared by thermal evaporation
under vacuum of 10-4 Pa.
The structural properties of these compounds in powder and thin
film forms were investigated by X-ray diffraction. The optical constants
(absorption coefficient and band gap) of the thin films were determined by
measurements of IR absorbance in the region 2.5 - 10 mm.
Analysis of the optical absorption spectra revealed the existence of two
direct energy gaps.
PACS numbers: 74.70.Dd, 68.55.-a, 78.66.Li
UDC 539.216, 538.911, 535.343
Keywords: Bi-Sb-Te-Se thin films, structural properties, IR absorption, direct