[1C01-10] Thin Film (TF)

3:00 PM - 3:15 PM JST(6:00 AM - 6:15 AM UTC)

[1C03] Fabrication of anatase Nb:TiO₂ epitaxial thin films with nonlinear depth-dependent composition profiles

*Kenichi Kaminaga¹, Ryota Kimura¹, Yuto Abiko¹, Shingo Maruyama^1,2, Yuji Matsumoto¹ (1. Tohoku University (Japan), 2. Shizuoka University (Japan))

Depth-dependent dopant control in oxide films can yield functions beyond uniform films and abrupt heterostructures. We previously found that a linear Nb gradient in anatase Nb:TiO₂ improves the transparency-conductivity balance. Here, we extend this concept to nonlinear profiles by fabricating 40-nm Nb:TiO₂ epitaxial films with sinusoidal Nb modulation using galvanomirror-scanning PLD. The “Sin-wave” film was designed so that the nominal Nb concentration varies from 0 to 20 at.% through the thickness while keeping the average at 10 at.%. Uniform and UP-graded films were prepared for comparison. XRD confirmed epitaxial growth and showed a broad peak with shoulder-like features for the Sin-wave film, indicating distributed local lattice parameters. SIMS NbO^- depth profiles showed smooth nonmonotonic variation, consistent with the designed sinusoidal Nb distribution. These results demonstrate nonlinear depth-profile design in Nb:TiO₂ epitaxial films.

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