Regensburg 2019 – scientific programme

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DS: Fachverband Dünne Schichten

DS 14: Poster

DS 14.42: Poster

Tuesday, April 2, 2019, 17:00–20:00, Poster E

Microstructuring of rf-sputtered VO2 thin films for improved transmittance properties — •Hannes Giese, Florian Kuhl, and Angelika Polity — Institute of Experimental Physics I and Center for Materials Research (ZfM/LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen

Vanadiumdioxide (VO2) is a material which changes its transmittance properties due to a temperature induced metal-to-insulator phase transition (MIT). The transmittance for infrared light in the monoclinic low temperature phase is much higher than in the tetragonal high temperature phase, thus VO2 is predestined for use as a smart window coating for an improved climate control in buildings. To gain a better optical impression and a higher transmittance in the visible range, one attempts to reduce the VO2 covered area by microstructuring but on the other hand to maintain the switching effect.

The VO2 thin films were deposited by radio-frequency sputtering (rf sputtering). Microstructuring was carried out by photolithography with different patterns and both, positive and negative photoresists. As last step ion beam etching (IBE) was used for structuring the samples to obtain different patterns in the VO2 thin film. The samples were characterized by UV/Vis spectroscopy for optical properties and light microscopy for determining the pattern sizes. The influence of different patterns, variation of covered area, etching parameters and size of the structures on the optical parameters was investigated to gain the best compromise between enhancing the transmittance in visible light and still a good switching efficiency for the MIT in the infrared range.