PhD student position (fmd) K 1726

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 ( and a member of the Leibniz Association (). You can find more details on the institute webpage: .

The Leibniz-Institut für Kristallzüchtung is currently looking for a

PhD Student (f/m/d)

for the 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 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 focusses on the synthesis of high-quality and ultra-HPGe single crystals. One of the major challenges is reducing and controlling the unintentional impurities (P B Al etc.) to achieve the required purity level typically corresponding to a net charge carrier density < 1010 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 to be addressed by finding new approaches and innovative process optimization.

In the host research section at IKZ a dedicated lab facility is available and you will work along with most experienced semiconductor researchers where your independent thinking is strongly supported and novel ideas are particularly -house expertise in crystal growth sample preparation and characterization combined with a state-of-the-art laboratory infrastructure provides outstanding opportunities to reach the research goal. Have we sparked your interest in synthesizing Ge crystals with impurity levels so low that these are among the purest materials on earth

The tasks as a PhD student in this international consortium will include

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 (like PTIS NAA AMS)

Developing a new algorithm/modelling 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 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.

You 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.

For information about the project please contact: Priv.-Doz. Dr. R. Radhakrishnan Sumathi
Tel.: 49(0)30 .

Have we aroused your interest

Then apply with a letter of motivation curriculum vitae and all relevant certificates by 20th of July. 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!