The Leibniz-Institut für Kristallzüchtung (IKZ) is a leading research institution in the area of science & technology as well as service & transfer of crystalline materials. Our goal is to enable solutions for urgent societal challenges (e.g. communication, artificial intelligence, climate protection, health etc.). by modern electronic & photonic technologies. The work covers the full spectrum from basic over applied research up to pre-industrial development and is performed in collaboration with national and international partners from university, academy and industry. The institute is part of the Forschungsverbund Berlin ( https://www.fv-berlin.de/ ) and a member of the Leibniz Association www.leibniz-gemeinschaft.de. You can find more details on the institute webpage: www.ikz-berlin.de. The SiGe-based Quantum Materials group at IKZ Berlin, Germany is offering a PhD student position (f/m/d) Isotope-pure silicon epitaxy for quantum photonic chips Are you excited by semiconductor materials science and quantum technology? This PhD project puts you at the forefront of silicon-based quantum photonics, combining epitaxy, nanofabrication, and quantum optics within a French-German collaboration. Silicon-on-insulator (SOI) provides a mature, industry-compatible platform for integrated quantum photonic circuits operating at telecommunication wavelengths, directly compatible with existing fiber networks. To realize fully functional quantum chips, however, the integration of reliable single-photon emitters remains a major open challenge. Among the most promising candidates are erbium (Er³⁺) ions in isotope-pure silicon, which feature extremely sharp atom-like optical transitions precisely in the telecom window, enabling low-loss photon transmission through standard optical fibers. In this PhD position, you will develop ultra-clean, isotope-pure SOI chips by molecular beam epitaxy (MBE) for highly coherent Er quantum light sources, a key step toward scalable quantum networks. In particular, you will: Innovate growth processes using silicon and germanium to introduce static strain in SOI Explore in-situ incorporation of individual Er ions in SOI device layers Operate and maintain large vacuum/epitaxy systems for isotope-pure Si epitaxy using 28 Si Leverage advanced in-house material characterization tools to understand and improve the nanoscale properties of your materials Collaborate with the leading groups in the quantum field, integrating your material developments in real quantum photonic chips, all within a research project together with partners from Institut Néel CNRS and Technical University of Munich (TUM) Center for Quantum Engineering (ZQE) Requirements We are looking for a candidate with strong communication skills, the assertiveness to work in an internationally positioned group and institute, and willing to formulate own scientific ideas and willing to help find technical solutions to plant-specific challenges. Furthermore, we expect: Master’s degree (or equivalent) in physics, chemistry, materials science or related field Solid knowledge in semiconductor materials, epitaxy, and thin film characterization (experience in any of these areas is a plus) Interest in quantum information science and quantum technology M otivation and capability to do scientific work, as well as its documentation and presentation Excellent written and oral communication skills in English IKZ is recognized as the provider and leading facility for the purification and crystal growth of isotope-pure semiconductor material e.g. for metrology, or cosmology and particle physics. Our re search group benefits from this position and is internationally recognized for the development and distribution of isotope-pure SiGe quantum material; join us if you are a material science enthusiast with a passion for pushing boundaries in a high-impact field. What we offer: The position is limited to three years. Payment is according to TVöD Bund (E13 75%) (Collective agreement for the public sector). The contract includes the usual social benefits (30 vacation days in a 5-day week, flexible working hours). The Leibniz-Institut für Kristallzüchtung actively promotes the development of young scientists and follows the guidelines of the Leibniz Association. The Leibniz-Institut für Kristallzüchtung actively supports a healthy work-life balance and is an equal opportunities employer. Female candidates are encouraged to apply and will be given preference if suitably qualified. Among equally qualified candidates, preference will be given to candidates with disabilities. IKZ promotes diversity. We welcome every qualified application, regardless of age, belief, disabilities, ethnic origin, gender, nationality, religion, or sexual orientation. For information about the project please feel free to contact: Dr. Kevin-Peter Gradwohl (kevin-peter.gradwohl@ikz-berlin.de) Have we aroused your interest? Then apply with a letter of motivation, curriculum vitae and all relevant certificates by 30.11.2025. To do so, please go to Job offers/jobs on our homepage and click on this advertisement and then on "Apply online". Please send us your complete application documents this way. We look forward to receiving your application!