Regensburg 2002 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 2: Transporteigenschaften
HL 2.4: Vortrag
Montag, 11. März 2002, 11:15–11:30, H13
Porous alumina photonic crystals obtained via nano-imprint method — •Jinsub Choi, Jörg Schilling, Kornelius Nielsch, Reinald Hillebrand, Manfred Reiche, Ralf B. Wehrspohn, and Ulrich Gösele — Max-Planck-Institute of Microstructure Physics, Weinberg 2, 06120 Halle
A photonic crystal based on perfect 2D porous alumina with a high aspect ratio was fabricated via imprint methods. Imprint methods are able to give a cm2-scale mono-domain porous alumina. An imprint stamp with 500 nm pitch and 260 nm height convex pyramid was fabricated by VLSI processing, namely, DUV-lithography, anisotropic etching, LPCVD Si3N4 deposition, and wafer bonding. After transferring the pattern on a polished aluminum under 5 kN/cm2, the aluminum was anodized in 1 wt% phosphoric acid at 195 V. Afterward, the porous alumina with over 100 µm depth was chemically widened in 10 wt% phosphoric acid at 30oC to adjust an r/a-ratio. An almost perfect plane along the Γ-K direction was obtained by cleaving the sample.
The reflection of the porous alumina photonic crystals with different r/a values was measured with an FT-IR microscope in Γ-M direction. For example, an r/a = 0.42 yields a photonic bandgap at 1µm in the H-polarization. The experimental results could be fit very well with plane-wave expansion methods and with reflection calculations assuming a dielectric constant of є = 2.0 for the anodized alumina.