Wang Yannan, Hirose Yasushi, Wakasugi Takuto, Masubuchi Yuji, Tsuchii Masato, Sugisawa Yuki, Sekiba Daiichiro, Chikamatsu Akira, Hasegawa Tetsuya
Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan.
Faculty of Engineering, Hokkaido University, N13 W8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan.
J Phys Chem Lett. 2021 Dec 30;12(51):12323-12328. doi: 10.1021/acs.jpclett.1c03673. Epub 2021 Dec 22.
TaN is a promising semiconductor photocatalyst which can generate H gas from water under visible light illumination. It is expected that TaN exhibits a strong anisotropy in its physical properties stemming from its highly anisotropic crystal structure. However, such anisotropic properties have not been verified experimentally due to the difficulty in synthesizing a large single crystal. Here, we report the synthesis of (010)-oriented TaN single-crystalline thin films by solid phase epitaxy on the (110) plane of perovskite LaAlO substrates. The obtained epitaxial thin films of TaN exhibited clear optical anisotropy (pleochroism) as predicted by previous first-principles calculations. The optical gap for ||[100] polarization (∼2.12 eV) was smaller than that for ||[100] polarization (∼2.27 eV).
氮化钽是一种很有前景的半导体光催化剂，在可见光照射下能从水中产生氢气。由于其高度各向异性的晶体结构，预计氮化钽在物理性质上表现出很强的各向异性。然而，由于难以合成大尺寸单晶，这种各向异性性质尚未通过实验得到验证。在此，我们报告了通过在钙钛矿型LaAlO衬底的(110)平面上进行固相外延生长来合成(010)取向的氮化钽单晶薄膜。所得的氮化钽外延薄膜表现出如先前第一性原理计算所预测的明显光学各向异性（多色性）。对于||[100]偏振的光学带隙（约2.12 eV）小于对于||[100]偏振的光学带隙（约2.27 eV）。
