Regensburg 2025 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 29: Poster II

HL 29.48: Poster

Tuesday, March 18, 2025, 18:00–20:00, P1

UV Photolithographic Fabrication of Photonic Structures on Diamond — •Nidhin Varghese, Oleg Peter, and Wolfgang Harneit — Institute of Physics,University of Osnabrück,Germany

The NV center in diamond is a point defect with promising quantum applications at room temperature, combining long spin relaxation times with optical excitation and state readout. Photonic structures such as micron-sized pillars help to increase the photon collection efficiency, improving the SNR ratio and enhancing sensitivity. NV centers in photonic structures can also be used to read out and control other spins, e.g., molecular qubits The top-down approach to fabricating photonic structures is straightforward and based on reactive ion etching of diamond. The process first requires a patterned etching mask, which is usually defined using electron beam lithography (EBL). Although EBL allows to make very small patterns, it is quite expensive and time-consuming. Using photolithographic processes could enhance industry adoption and increase accessibility to diamond quantum technology for research labs that do not have access to EBL. Here, we present a novel approach to nano-pillar fabrication based on direct (UV) laser writing lithography. An easy-to-use epoxy stage was developed for spin coating of photoresists on very small substrates, which largely supresses the formation of edge beads. The photonic pillar structures were fabricated by lithography and ion etching, and characterized. Confocal fluorescence scans demonstrated the increased photon output performance. CW-ODMR measurements confirmed the presence and accessibility of NV centers.

Keywords: Diamond; NV Center; Photolithography; ICP-RIE; Quantum Technology