Significance of in-plane oxygen vacancy rich non-stoichiometric layer towards unusual high dielectric constant in nano-structured SnO2

Influence of non stoichiometric layer to the possible contribution towards the unusually high dielectric constant of n-type SnO2 is discussed. Oxygen deficient and oxygen rich environments during the growth of SnO2 nanoparticles synthesized from the as prepared SnO2 quantum dots (QDs) of ∼2.4 nm have enabled creation of various defects states; however, it results to similar dimension of NPs. Defects states bring in strong changes in dielectric property including other electrical properties. Oxygen vacancies related defects have been spectroscopically elucidated using Raman spectroscopy and photoluminescence measurements. The study offers a plausible correlation between oxygen vacancies and unusually high dielectric constant of SnO2. In-plane oxygen vacancy is found to be responsible for enhanced dielectic value. The understanding of phenomena involved in the colossal permittivity can be utilized for tuning and the engineering of the macroscopic device applications.