Synthesis and characterization of Bi doped Se-Te nanostructured thin films

The nanostructure formation has been revealed in different types of materials and therefore an increasing interest has been witnessed in recent years to study the amorphous materials. Nano-structured materials show dramatic changes in their structural, optical and electrical characteristics due to the decrease in size below excitonic limit and provide new physical and chemical properties. In the present research work amorphous Se80Te20−xBix (x = 3 and 6) was prepared by melt quenching techniques. Nano-structured thin films of amorphous Se80Te20−xBix have been obtained using physical vapor condensation process on glass/Si wafer substrate. The morphology of amorphous Se80Te20−xBix films was scanned by employing field emission scanning electron microscope (FESEM). The optical absorption and reflection spectra of nano-structured films were inspected by UV/VIS/NIR spectrophotometer. The optical absorption analysis indicates the non-direct transitions predominate in nano-structured Se80Te20−xBix films. The extinction coefficient and absorption coefficient are found to decrease while optical energy band gap and the refractive index increase with Bi contents in Se-Te system.