tailieunhanh - Báo cáo hóa học: " Anodization of nanoporous alumina on impurityinduced hemisphere curved surface of aluminum at room temperature"

Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Anodization of nanoporous alumina on impurityinduced hemisphere curved surface of aluminum at room temperature | Chung et al. Nanoscale Research Letters 2011 6 596 http content 6 1 596 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Anodization of nanoporous alumina on impurity-induced hemisphere curved surface of aluminum at room temperature Chen-Kuei Chung Ming-Wei Liao Chun-Te Lee and Hao-Chin Chang Abstract Nanoporous alumina which was produced by a conventional direct current anodization DCA process at low temperatures has received much attention in various applications such as nanomaterial synthesis sensors and photonics. In this article we employed a newly developed hybrid pulse anodization HPA method to fabricate the nanoporous alumina on a flat and curved surface of an aluminum Al foil at room temperature RT . We fabricate the nanopores to grow on a hemisphere curved surface and characterize their behavior along the normal vectors of the hemisphere curve. In a conventional DCA approach the structures of branched nanopores were grown on a photolithography-and-etched low-curvature curved surface with large interpore distances. However a high-curvature hemisphere curved surface can be obtained by the HPA technique. Such a curved surface by HPA is intrinsically induced by the high-resistivity impurities in the aluminum foil and leads to branching and bending of nanopore growth via the electric field mechanism rather than the interpore distance in conventional approaches. It is noted that by the HPA technique the Joule heat during the RT process has been significantly suppressed globally on the material and nanopores have been grown along the normal vectors of a hemisphere curve. The curvature is much larger than that in other literatures due to different fabrication methods. In theory the number of nanopores on the hemisphere surface is two times of the conventional flat plane which is potentially useful for photocatalyst or other applications. PACS . Keywords anodic aluminum oxide porous .