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| Anodic aluminum oxide (AAO) is a typical self-ordered porous material. Lowering the anodization voltage during the growth process, the pores will branch. To apply a periodic anodization voltage, one-dimensional porous Bragg stack with periodic pore density can be fabricated. By adjusting the pore density period properly, photonic band gap can be located in the visible light region, and the anodic aluminum oxide will display vivid strutural color. Immersing the anodic aluminum oxide in analyte, the structural color changes with the refractive index of analyte. In this paper, by employing a modified voltage-controlled anodization method and subsequent chemical etching process, chemical sensors made of porous AAO Bragg stacks with aluminum substrates are fabricated successfully. Compared with the similar ones reported before, this kind of sensors shows much higher sensitivity and possesses more rugged construction. The color changes between the analytes with relatively large difference in refractive index can be distinguished simply by the naked eyes.
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| Keywords:anodic aluminum oxide; bragg stacks; chemical sensor |
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