Titanium oxide is a perspective material for creating photonic crystals due to its high transparency in a visible spectral range and the high refractive index. Among the variety of approaches to the preparation of titanium oxide photonic crystals, the most promising method is the anodizing of titanium under periodic anodizing conditions [1, 2]. Photonic crystals based on titanium oxide are promising for optoelectronic applications, for example as components of solar cells and photodetectors.
The developed technique [3] allows one to control the position of the photonic band gap of anodic titanium oxide photonic crystals in the range of 430–800 nm with an accuracy better than 98.5%. The suggested method can be also applied to control the photonic band gap position in the IR wavelength range. The prepared titanium oxide photonic crystals are promising as the refractive index sensors owing to the high sensitivity (360 nm per refractive index unit) of the photonic band gap position to the refractive index of a liquid filling the pores.
This work was supported by the Russian Science Foundation under Grant No. 17-73-10471.
[1] N.A. Sapoletova, S.E. Kushnir, K.S. Napolskii, Anodic titanium oxide photonic crystals prepared by novel cyclic anodizing with voltage versus charge modulation // Electrochemistry Communications, 2018, v. 91, pp. 5–9. DOI: 10.1016/j.elecom.2018.04.018.
[2] K. Wang, G. Liu, N. Hoivik, E. Johannessen, H. Jakobsen, Electrochemical engineering of hollow nanoarchitectures: Pulse/step anodization (Si, Al, Ti) and their applications // Chemical Society Reviews, 2014, v. 43, pp. 1476–1500. DOI: 10.1039/C3CS60150A.
[3] G.A. Ermolaev, S.E. Kushnir, N.A. Sapoletova, K.S. Napolskii, Titania photonic crystals with precise photonic band gap position via anodizing with voltage versus optical path length modulation // Nanomaterials, 2019, v. 9, 651. DOI: 10.3390/nano9040651.