[OPTICAL REVIEW Vol. 17, No. 6 (2010) 553-556]
© 2010 The Japan Society of Applied Physics
Anti-reflective Effect of Transparent Polymer by Plasma Treatment with End-Hall Ion Source and Optical Coating
Jin-Cherng HSU1, Paul W. WANG2, Yung-Hsin LIN3*, Huang-Lu CHEN3, Yu-Yun CHEN3, Yeong-Der YAO3, and Jen-Chieh YU3
1Department of Physics, Fu Jen Catholic University, 510 Chung-Cheng Rd., Hsinchuang, Taipei Hsien 24205, Taiwan
2Department of Physics, Bradley University, 1501 W. Bradley Ave., Peoria, IL 61625, U.S.A.
3Graduate Institute of Applied Science and Engineering, Fu Jen Catholic University, 510 Chung-Cheng Rd., Hsinchuang, Taipei Hsien 24205, Taiwan
(Received April 29, 2010; Accepted September 8, 2010)
The surface of poly(methyl methacrylate) (PMMA) was treated by plasma with an end-Hall ion source in vacuum in order to enhance its anti-reflectivity. The cone-shaped bumps induced by the plasma etching have shown an anti-reflective effect. Moreover, PMMA has poor thermal durability due to its low melting point; therefore, the etched PMMA was further coated by a 5 nm thick SiO2 film after 900 and 1300 s plasma etching. Samples after SiO2 coating were thermally annealed at temperature of 70 °C for 1 h. Experiments show that transmittance was increased after 5 nm thick SiO2 coating. The of transmittance of PMMA after both sides treated by 900 s plasma etching and 5 nm SiO2 coating was not changed after thermal annealing. However, without SiO2 coating the transmission was reduced 1% after annealing. Atomic force microscope (AFM) demonstrated that the nano-structures of cone-shaped bumps were formed on the PMMA after plasma etching and a smoother nano-structured pattern preserved the transmittance of the PMMA after both sides treated by 900 s plasma etching and 5 nm SiO2 coating. Three dimensional photonic crystal formed by uniformly distributed cone-shaped bumps was assumed to result in the reduction of the anti-reflectivity of treated PMMA.
Key words: poly(methyl methacrylate) (PMMA), anti-reflectivity, plasma etching, thermal stability of transmittance
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