Energy band structure investigation of blue and green light emitting Mg doped SnO2 nanostructures synthesized by combustion method

Tin oxide (SnO2) and Mg doped (2, 4, 6, and 8 wt%) SnO2 nanoparticles were synthesized by the self-propagating solution combustion synthesis using citric acid as fuel. The characterization of samples was done by X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), UV–visible spectroscopy, SAED and photoluminescence (PL). XRD pattern and TEM studies show that the synthesized particles are of average size 30 nm and they are in tetragonal rutile structure of SnO2. Combined blue and green emission is seen in 4 wt% Mg doped SnO2 and intensity of blue band is increased with respect to increase in Mg dopant concentration which is attributed to increase in population of oxygen vacancies. The PL emission in blue and green region is due to the doubly charged state (Vo2+) of oxygen and tin interstitial defects respectively and is explained with an energy band diagram.