Preparation and characterization of Eu-doped SnO2 nanostructures for hydrogen gas sensing

This paper presents effect of europium doping on the structural, optical and gas sensing properties of SnO2 nanoparticles. XRD (X-ray diffraction) and Raman results confirmed tetragonal rutile structure of both undoped as well as Eu-doped SnO2 nanoparticles. The crystallite size has decreased systematically with increase in dopant concentration as confirmed from XRD and TEM (Transmission electron microscopy) investigations. The shifting and broadening of Raman bands has been explained on the basis of phonon confinement effect. Raman spectra exhibited bands centered at 567 and 523 cm(-1) which are associated with the Raman surface modes and whose contribution has been found to increase with increase in the dopant concentration. The intensity of emission peaks in the PL (Photoluminescence) spectra has been found to decrease with increase in dopant concentration which can be attributed to the concentration quenching effect. The operating temperature of all the sensors has been investigated which optimized at 350 degrees C. There has been a significant enhancement in sensor response towards hydrogen due to Eu doping which optimized at 3 % dopant concentration.