Freiburg 2024 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 57: Poster VIII

Q 57.16: Poster

Thursday, March 14, 2024, 17:00–19:00, Aula Foyer

Optical coherence tomography of encapsulated two-dimensional materials using extreme ultraviolet radiation from high-harmonic generation sources — •Felix Wiesner¹, Julius Reinhard^1,2, Johann J Abel¹, Martin Wünsche¹, Gerhard G Paulus^1,2, and Silvio Fuchs^1,2,3 — ¹Institute of Optics and Quantum Electronics, Friedrich Schiller University Jena, Jena, Germany — ²Helmholtz Institute Jena, Jena, Germany — ³University of Applied Sciences Mittweida, Laserinstitut (LHM, Mittweida, Germany

Atomically thin materials, such as graphene or transition-metal dichalgonides (TMDs), demonstrate exciting physical properties. For the majority of applications, the monolayers must be encapsulated for passivation, protection, or functionalization. Although many techniques exist to characterize the monolayers themselves, methods for imaging encapsulated monolayers are lacking.

Coherence tomography with extreme ultraviolet light (XCT) is a high resolution, high sensitivity technique for axial imaging. The high spatial resolution is enabled by the use of broadband extreme ultraviolet (EUV) light produced by high-harmonic generation (HHG). Consequently, XCT promises to provide important information on the structure of samples containing encapsulated monolayers.

This study applies XCT to the investigation of graphene layers in a silicon encapsulation. Mono-, bi-, and trilayers of encapsulated graphene can be differentiated. Furthermore the interface roughness and the thickness of native oxide layers can be reconstructed. We discuss the applicability of the method to additional types of samples.

Keywords: High Harmonic Generation; Imaging; Extreme Ultraviolet; Optical Coherence Tomography; 2D materials