Analysis of electronic, Raman and UV-vis spectra for Zn11Se11, Zn11S11, and ternary alloys Zn11SnSe11-n(n= 1-11) A DFT/TDDFT study.

Abstract

Zn 11 Se 11 , Zn 11 S 11 , and ternary alloys from Zn 11 S n Se 11-n (n = 1-11), with cubic structures represented by nanostructures called tetramantane, have been studied theoretically by investigating the electronic properties, Raman and UV-vis spectra. LUMO and HOMO levels were observed to change with the number of the sulfur atoms. The (HOMO-LUMO) gap for Zn 11 Se 11 (2.377205eV) increased with the sulfur atoms. Zn 11 S 8 Se 3 have an energy gap (3.061305eV) less than others ternary alloys. The calculated energy gap of Zn 11 S 11 (3.597374eV) is in a high agreement with experimental value (3.6 eV). Raman spectra for ternary alloys Zn 11 S n Se 11-n content peaks result from the connection of (Zn 11 Se 11 +Zn 11 S 11) peaks, Zn 11 Se 11 has peak at 260.42 cm-1 shifts from the experimental value by a small deviasion which is produced due to the confinement effect. UV-vis spectra for ternary alloys shifted to a higher energy level with the increase in the number of sulfur atoms and dramatically close to Zn 11 S 11 UV-vis spectrum except Zn 11 S 8 Se 3 has λ max at 342 nm. These nanostructures are suitable to be used in different applications such as lenses, photoelectronic devices, solar energy, and biosensors. DFT/TDDFT at the B3LYP level with SDD basis functions is used. All the calculations are completed using the Gaussian 09 program.