open access

https://hdl.handle.net/2115/90698

Orthorhombic distortion-induced anatase-like optoelectronic properties of rutile TiO2

英語

2022-11-14

AIP Publishing

Journal of Applied Physics

132(18)

185301

Titanium dioxide (TiO2) is an excellent photocatalyst and transparent conducting oxide. It has two major crystal structures: rutile and anatase. Anatase TiO2 is valuable from an industrial point of view because it typically displays better photocatalytic and electronic transport properties than rutile TiO2. To further extract the functional properties of TiO2, understanding the correlation between the electronic structure and the crystal structure is essential. Because the electronic structure strongly depends on the crystal structure, introducing lattice distortion to rutile TiO2 should effectively modulate its electronic structure. Here, we show that Nb-doped rutile TiO2 epitaxial films on (1 (1) over bar 00) alpha-Al2O3 substrates exhibit anatase-like optoelectronic properties due to orthorhombic lattice distortions and experimentally observe the change in the electronic structure. Reducing the film thickness increases the orthorhombic distortion ratio (b/a) up to 3.4%. As b/a increases, the carrier effective mass decreases from 35 to 3 m(0) (m(0): electron mass) and the optical bandgap significantly increases. The present observations provide insight into regulating the TiO2 physical properties and should be beneficial for designing TiO2-based photocatalysts and transparent conducting electrodes. Published under an exclusive license by AIP Publishing.

学術雑誌論文

Version of Record

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Binjie Chen, Kungwan Kang, Hyoungjeen Jeen, Yuqiao Zhang, Jinghuang Lin, Bin Feng, Yuichi Ikuhara, Sena Hoshino, Katsuyuki Matsunaga, and Hiromichi Ohta , "Orthorhombic distortion-induced anatase-like optoelectronic properties of rutile TiO2", Journal of Applied Physics 132, 185301 (2022) https://doi.org/10.1063/5.0119725 and may be found at https://doi.org/10.1063/5.0119725

0021-8979