Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (03): 749-753.doi: 10.3866/PKU.WHXB20110310

• PHYSICAL CHEMISTRY OF MATERIALS • Previous Articles     Next Articles

Fabrication of Large Area of Anodic Aluminum Oxide Ultrathin Film Directly onto an ITO Electrode with a Ti Buffer Layer

XIAO Lixin, DUAN Laiqiang, CHAI Junyi, WANG Yun, CHEN Zhijian, QU Bo, GONG Qihuang   

  1. State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, P. R. China
  • Received:2010-10-12 Revised:2010-12-20 Published:2011-03-03
  • Contact: XIAO Li-Xin, GONG Qi-Huang E-mail:lxxiao@pku.edu.cn;qhgong@pku.edu.cn
  • Supported by:

    The project was supported by the National Found for Fostering Talents of Basic Science (NFFTBS) (J0630311), National Natural Science Foundation of China (10934001, 60907015, 10821062) and National Key Basic Research Program of China (973) (2007CB307000, 2009CB930504).

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Abstract:

An anodic aluminum oxide (AAO) ultrathin film (~140 nm, about half the thickness of the original Al film) was successfully fabricated directly onto an indium tin oxide (ITO) electrode without the erosion of ITO by a two-step anodization process in 0.3 mol·L-1 O2SO4 solution at a constant voltage of 20 V. Here, a thin titanium buffer layer was included between the ITO electrode and the Al film by radio frequency (RF) magnetron sputtering. A large area (about 4 cm2) of porous alumina with nanoscaled channels perpendicular to the substrates was obtained. The average pore diameter and the pore interspace were approximately 30 and 60 nm, respectively. We found that the Ti buffer layer with a thickness of 10-40 nm between the Al layer and the ITO substrate played a critical role in improving the adhesion and ensuring ITO protection, which could not be duplicated by other metals, e.g., Cr, Au, Ag, and Cu. UV-visible transmittance spectra confirmed that the Ti buffer layer was oxidized and became transparent TiO2 and that 10-20 nm of the Ti buffer layer together with the two-step anodization process is suitable for high transparency. Therefore, the AAO specimen possessing a high nanoscale regularity and transparency may have potential use in photonics, photovoltaics, and nanofabrications.

Key words: Anodic aluminum oxide, Ultrathin film, ITO transparent electrode, Titanium buffer layer, Radio frequency magnetron sputtering