PhD student position (f/m/d) · K 17/26

The Leibniz-Institut für Kristallzüchtung (IKZ) is a leading research institution in the field of science & technology as well as service & transfer of crystalline materials. Our goal is to enable solutions for pressing societal challenges (e.g. communication, artificial intelligence, climate protection, health, etc.) through modern electronic & photonic technologies. The work covers the entire spectrum from basic and applied research to pre-industrial development and is carried out in cooperation with national and international partners from universities, academies and industry. The Institute is part of the Forschungsverbund Berlin (https://www.fv-berlin.de) and a member of the Leibniz Association (https://www.leibniz-gemeinschaft.de). More details on the institute webpage: https://www.ikz-berlin.de.

PhD Student (f/m/d)

Topic: “Processing, crystal growth and characterization of ultra-high purity germanium (HPGe) for radiation detection applications”.

High-purity germanium (HPGe) single crystals play a key role in radiation detection, particularly in gamma-ray spectroscopy, neutrinoless double-beta (0νββ) decay experiments, and low-mass dark matter searches. HPGe detectors offer excellent energy resolution with large detector sizes for high radiation detection efficiency. As a partner in the grand international research collaboration LEGEND (Large enriched germanium experiment for 0νββ-decay), our research focuses on the synthesis of high-quality and ultra-HPGe single crystals. One of the major challenges is to reduce and control the unintentional impurities (P, B, Al, etc.) to achieve the required purity level, typically corresponding to a net charge carrier density < 10⁻¹⁰ cm⁻³ (i.e. impurities below ppt level).

Predicting impurity redistribution during HPGe zone refining is highly complex, and reliable advanced modelling can accelerate process optimization. Another challenge is the detection and quantification of ultra‑low impurity concentrations. These problems are addressed by finding new approaches and innovative process optimization.

Tasks

• Czochralski growth of HPGe crystals and characterization
• Systematic investigations of the processes, like H₂ reduction of GeO₂ and zone purification
• Identification and quantification of ultra‑low level impurities using unique measurement techniques (e.g. PTIS, NAA, AMS)
• Developing a new algorithm/modeling to predict impurity distribution in the material
• Fabrication, characterization of HPGe detectors and feedback to crystal growth

Required qualifications

• Master degree in physics, chemistry, material science or other related disciplines
• Strong background in semiconductor physics and materials processing
• Knowledge on basic characterization of materials
• Motivation and passion for scientific research
• Ability to work independently in a laboratory research environment
• Very good written and spoken English

Prior hands‑on experience or skills in the following fields is an asset

• Hand‑on experience in melt growth (e.g. Czochralski, Bridgman)
• Knowledge in inorganic chemistry, doping control, electrical characterization techniques
• Basic knowledge in German language
• Programming/Software skills (e.g. Python, Matlab, Origin)

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 Institute actively promotes the development of young scientists and follows the guidelines of the Leibniz Association.

The Institute 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. The Institute promotes diversity. We welcome every qualified application, regardless of age, belief, disabilities, ethnic origin, gender, nationality, religion or sexual orientation.

You will enjoy working in a motivated team, and you will gain unique experience in the renowned crystal growth institute and work on potentially ground‑breaking technologies for the production of semiconductor materials and its related research.

Contact

Priv.-Doz. Dr. R. Radhakrishnan Sumathi
Tel.: +49(0)30 246 499 401 radhakrishnan.sumathi@ikz-berlin.de

Application

Then apply with a letter of motivation, curriculum vitae, and all relevant certificates by 20th July. Please go to Job offers/jobs on the homepage, click on this advertisement, and then click on “Apply online”. We look forward to receiving your application!