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DF: Fachverband Dielektrische Festkörper
DF 14: Various Topics II
DF 14.7: Talk
Wednesday, March 22, 2017, 17:20–17:40, GER 37
Mid-infrared optical and plasmonic devices enabled by area-selective ion beam doping of silicon — •Martin Hafermann1, Jad Salman2, Raymond Wambold2, Chenghao Wan2, Jura Rensberg1, Mikhail A. Kats2, and Carsten Ronning1 — 1Institute of Solid State Physics, Friedrich Schiller University Jena, Max-Wien-Platz 1, 07743 Jena, Germany — 2Department of Electrical and Computer Engineering, University of Wisconsin - Madison, 1415 Engineering Drive, Madison, WI 53706, USA
The free charge carrier concentration of semiconductors is tunable over several orders of magnitude by impurity doping. Comparable to noble metals in the ultraviolet-visible spectral region, highly doped semiconductors possess "metal-like" optical properties but in the mid-infrared regime. Thus, the plasma frequency of these materials can be adjusted over a wide range by controlling the doping concentration. In this work, we fabricated optical and plasmonic devices in the mid-infrared using area-selective ion implantation of phosphorous through lithographically defined masks into silicon and subsequent annealing. Reaching doping concentrations on the order of 1021 cm-3 resulted in cross-over frequencies (where εreal = 0) in the range of 4 µm. Thus, we demonstrate diffractive optical elements such as Fresnel zone plates and diffraction gratings, as well as plasmonic devices like frequency selective surfaces. Our process results in optical devices that are CMOS compatible, completely planar and monolithic, thus stackable, as well as robust against high temperatures and physical erosion.