Advisor : P. C. Yu Speaker : G. S. Hong Optoelectronics Research Centre, Tampere University of Technology, Korkeakoulunkatu 3, 33720, Tampere, P.O. Box 692, Tampere, Finland

 Introduction  Experiment  Results  Conclusion

 Moth-eye AR structures.  AlInP has a very large band gap (1.3~2.4eV) and high transparency.  This letter demonstrates moth-eye antireflection coatings fabricated by UV-nanoimprint lithography (NIL) on AlInP/GaAs structure. Introduction moth’s headmoth-eye

The yield is approximately 95% over an 4 cm^2 consisted of 4.4x1e9 nanocones. Arrays of metallic nanocones fabricated by UV-nanoimprint lithography Juha M. Kontio *, Janne Simonen, Juha Tommila, Markus Pessa Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, FIN-33101, Tampere, Finland

Fabrication steps (1) Laser interference lithography (LIL)UV - NIL

Fabrication steps (2) PMMASi Ge UV-NIL resist

A :30/170/370 nm (top diameter/base diameter/height) B : 50/220/370 nm C : 80/300/440 nm Reference : 1 um AlInP Simulation & Measurement

The simulated values are lower than the measured ones partly due to :  The imperfect model of the dielectric function.  The roughness of the etched surfaces.  The silver mirror used as a reference in the measurements. Arithmetic average reflectivities

Reflection of the laser GaAs’PL Absorption of the laser and the PL in the AlInP layer PL intensities

 An average reflectivity of 2.7% was achieved for wide spectral range 450–1650 nm.  Using PL measurements, we have shown that the surface recombination and patterning induced losses are low.

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