IOQ-Kolloquium / Dr. Nico Klingner (Helmholtz-Zentrum Dresden-Rossendorf)

Focused ion beam (FIB) technology has evolved from a versatile microfabrication and imaging tool into a powerful platform for atomic-scale materials design, enabling the modification, doping, and restructuring of materials with nanometer precision. Combined with ultra-high-vacuum (UHV) operation, FIB finds broad application in quantum device fabrication, from single-photon emitter production to quantum-grade material processing [1]. Our research advances FIB capabilities toward unprecedented applications, and we present our latest technological developments alongside their uses in nanotechnology and quantum science.

Gas Field Ion Sources (GFIS) generate the world's smallest ion beams using helium or neon (sub-nanometer diameter). We exploit this capability to realize an ultralong, high-density data storage concept in radiation-resistant silicon carbide, based on optically active atomic-scale defects [2]. GFIS beams can also trigger a local phase transformation from β- to γ-Ga₂O₃ through ion-induced lattice disorder, enabling site-specific tuning of electronic and optical properties for advanced device applications [3,4]. We further present the extension of this source concept to heavier noble gases—argon, krypton, and xenon—for high-precision sputtering.

Liquid Metal Alloy Ion Sources (LMAIS) provide access to a wide range of elemental and isotopic species. We use them to induce defects that act as single-photon emitters for quantum photonics: Si⁺ [5] and C⁺ ions [6] have been implanted into silicon to create G- and W-centers emitting in the telecom O-band, making them ideal for fiber-optic quantum networks. Ongoing LMAIS development aims to improve source reliability and lifetime while expanding the accessible range of ion species. In collaboration with Raith GmbH, an industrial-grade emitter fabrication and characterization system is under development.

As device miniaturization reaches the quantum limit, placing individual dopant atoms with nanometer precision becomes critical for quantum applications and we will present our latest efforts for single ion implantation. These capabilities directly support EquSpace, an EIC Pathfinder Open project building a scalable donor spin qubit platform in silicon.

[1] Höflich, Katja, et al. Applied Physics Reviews 10.4 (2023).
[2] Hollenbach, M., et al. Advanced Functional Materials 34.27 (2024): 2313413.
[3] Azarov, Alexander, et al. Nature Communications 14.1 (2023): 4855.
[4] Bektas, Umutcan, et al. arXiv preprint arXiv:2505.03541 (2025).
[5] Hollenbach, M., et al. Nature Communications 13.1 (2022): 7683.
[6] Hollenbach, M., et al. Advanced Quantum Technologies 8.1 (2025): 2400184.