Interplay between External Strain and Oxygen Vacancies on Raman Spectra of SnO₂

Comprehensive first-principle calculations on strained SnO₂ crystal structure indicate that the formation energy of different types of oxygen vacancies depends on the external strain. Many novel Raman modes can be observed, their intensities and positions are strongly dependent on applied stain, which can be ascribed to crystal symmetry destruction by oxygen vacancies. Applied strain can compress/stretch distances between Sn and O atoms; therefore, Sn–O band vibration frequencies can be adjusted accordingly. Our calculated results disclose that the Raman spectra of SnO₂ crystal structure with different types of oxygen vacancies are obviously different, which can be used to identify the oxygen vacancy types in strained SnO₂ crystal structures.