Dresden 2020 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 30: Poster I
HL 30.37: Poster
Dienstag, 17. März 2020, 13:30–15:45, P3
Switchable THz wavefront modulators made of thermocromic VxW 1−x O 2 thin films — •Janine Lorenz1, Florian Kuhl1, Angelika Polity1, Yan Zhang2, and Peter J. Klar1 — 1Institute of Experimental Physics I and Center for Materials Research (ZfM/LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, DE-35392 Giessen, Germany — 2Beijing Key Lab for Metamaterials and Devices, Capital Normal University, Beijing, China
Due to the rapid progress in the reasearch field of terahertz generation and detection over the last years, terahertz applications have recently gained a lot of interest. Similar to VO 2 the insulator to metal transition (IMT) in thermochromic VxW 1−x O 2 allows us to design thermally switchable THz optics.
Here we present microfabricated resonator structures in rf-sputtered VxW 1−x O 2 thin films. The fabrication of the resonators is realised by photolithography and ion beam etching. Modulation properties of the resonators can be improved by depositing TiO 2 buffer layers onto the c-sapphire substrates used.
In comparison to VO 2 , the switching temperature of VxW 1−x O 2 can be reduced and tuned by varying the concentration x of tungsten. Measurements on unstructured thin films show typical switching temperatures for VO 2 of about 55 ∘C and 35 ∘C for VxW 1−x O 2 with x between 1 and 2 %. The modulating behavior of the resonator structures in the insulating and metallic phase was investigated by terahertz time-domain spectroscopy. Switchable devices are obtained since THz modulation only occurs in the metallic phase.