AVS 51st International Symposium
    Nanometer-scale Science and Technology Thursday Sessions
       Session NS1-ThM

Paper NS1-ThM6
Nanotip Arrays Fabricated by One-step and Self-masked ECR-Plasma Etching and Their Applications for Field Emission, Antireflection and Sensing

Thursday, November 18, 2004, 10:00 am, Room 213C

Session: Nanoscale Fabrication
Presenter: L.C. Chen, National Taiwan University, Taiwan
Authors: L.C. Chen, National Taiwan University, Taiwan
J.S. Hsu, National Taiwan University, Taiwan
H.C. Lo, Academia Sinica, Taiwan
I.F. Huang, National Taipei University of Technology, Taiwan
K.H. Chen, Academia Sinica, Taiwan
C.R. Lin, National Taipei University of Technology, Taiwan
C.F. Chen, National Chiao-Tung University, Taiwan
Correspondent: Click to Email
Well-aligned nanotip arrays with a nanotip density as high as 10^12 cm^-2 were achieved by a single-step electron cyclotron resonance plasma process using gas mixtures of silane, methane, argon and hydrogen. Formation of SiC cap was observed on each individual nanotip, implying a self-mask etching mechanism. This dry-etching technique was applied to a variety of substrates such as Si, GaN, GaP, Al, sapphire and glass, indicating its general applicability. The nanotip arrays so produced showed superior field emission as well as antireflection properties. The extremely sharp tip geometry provides large field enhancement, therefore a low turn-on field (<1V/micron), while the sub-wavelength nanostrutured surface exhibits an ultra low reflectivity (<0.1%) in visible and IR. The latter property can be explained by a simple gradient index model. Furthermore, the nanotip arrays dispersed with Ag nanoparticles also showed excellent surface enhancement in Raman scattering (SERS). By optimizing the size of Ag nanoparticle and inter-particle distance, SERS of 8-order has been achieved, suggesting potential application of nanoparticle-dispersed nanotip arrays in molecular sensors.