Terahertz Spectroscopic Investigation of Lanthanide-Doped Nano-TiO2
FENG Xiu-jun1, HUANG Wan-xia1*, SHI Qi-wu1, ZHANG Yu-bo1, LUO Yi1, ZHANG Ya-xin2
1. College of Materials Science and Engineering, Sichuan University, Chengdu 610064, China 2. Terahertz Research Center, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China
Abstract:Lanthanide-doped nano-TiO2 samples with different Ti/Ln (Ln=Ce, Nd, and Sm) were synthesized by sol-gel method. The samples were characterized by X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS) and terahertz time-domain spectroscopy(THz-TDS). The results indicate that Ce, Nd, and Sm ions were uniformly dispersed into the TiO2; and the infrared activities of lanthanide-deped nano-TiO2 were much stronger than Undoped nano-TiO2, the refractive index of anatase TiO2 declines with frequency increasing in the frequency range of 0.2~1.70 THz at room temperature, and it exhibits anomalous dispersion. Unique characteristic absorption peaks at 1.35 and 1.58 THz were observed from Ce-doped nano-TiO2. Compared with undoped nano-TiO2, the absorption edges of Ce-doped nano-TiO2 were red-shifted remarkably and those of Nd and Sm ions doped nano-TiO2 were blue-shifted. Sm-doped nano-TiO2 has induced the least dielectric losses in the frequency range of 0.2~1.7 THz, and the average value is 0.05.
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