Chalcogenides: Bulk and Thin Films

Chalcogens are the chemical elements of group 16 of the periodic table. Oxygen is treated separately from other chalcogens; it is even excluded from the term ‘chalcogen’ altogetherdue to its very different chemical behaviour from sulfur, selenium, tellurium and polonium. The heavier chalcogens have vacant d orbitals. A chalcogenide consists of at least one chalcogen element and one electropositive element. The term chalcogenide is more commonly reserved for sulfides, selenides and tellurides rather than oxides. The interest in these materials arises particularly due to their ease of fabrication in the form of bulk and thin films. Generally, chalcogenides have a large glass-forming region and thus, their physical properties can be tuned via chemical composition. These glasses have drawn great attention due to their striking electrical, optical and thermal properties, which ary with composition, heat treatment, irradiation, glass forming methods, etc. There is a high tendency for the atoms to link together to form link chains in chalcogenides. In general, the atomic bonding is more rigid than that of organic polymers and more flexible than that of oxide glasses. This chapter presents the method of fabrication of chalcogenides in bulk and thin film forms.