Structural, optical, and photoluminescence properties of erbium doped TiO2 films

TiO2 thin films doped with low percentages (3, 7, and 10 at.%) of Er3+ have been synthesized by sol gel spin coating technique. The influence of erbium concentration on the physical properties was analyzed using different characterization techniques such as X-ray diffraction, Raman spectroscopy, TEM analysis, EDS-SEM, AFM, UV-Visible transmittance spectroscopy, photoresponse and photoluminescence. The doped films exhibited significant modifications on the structural, optical and electrical properties due to the incorporation of erbium ions. The band gap energy was red shifted by Er doping indicating an improvement in visible light absorption. Intense Er3+-based emission peaks in the range 520-560 nm were observed for all samples. It was observed that Er-dopant concentration had direct impact on photoluminescence intensity.