Jülich: Master Thesis - MBE Growth and Phase Control of Stoichiometric Cr-Te Thin Films for Ferroelectric Applications

The Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) in Forschungszentrum Jülich is a center of excellence in advanced transmission electron microscopy (TEM) for addressing topical problems in materials science, solid state physics, chemistry, biology and soft matter. Systematic characterisation of materials is carried out using the latest TEM techniques, including aberration-corrected imaging, electron energy-loss spectroscopy, electron holography and electron ptychography, allowing for the measurement of not only structure and composition but also functional properties of materials with nanometer to atomic spatial resolution and high temporal resolution. At the subinstitute Physics of Nanoscale Systems (ER-C-1) we carry out systematic characterizations using various complementary techniques, including the latest TEM based techniques, such as electron holography, HR-(S)TEM, high energy resolution spectroscopy, 4D-STEM, and ptychography. This enables the measurement of, e.g., electrical potentials and magnetic fields, polarization fields, built-in potentials, strain, and carrier dynamics on nanometer scales with high temporal resolution.

Your Job:

This Master’s thesis focuses on the growth of stoichiometric chromium telluride (CrTex) thin films using molecular beam epitaxy (MBE), with an emphasis on achieving controlled stabilisation of the Cr4Te5 phase.

In addition to phase engineering, the project will examine how stoichiometry, structural quality and defect formation influence the potential ferroelectric functionalities of the material. In the first phase of the project, growth conditions will be tuned across the Cr-Te phase space and structural properties will be evaluated with a focus on next-generation devices. In the second phase of the project, electron-transparent specimens will be prepared for TEM examination using plasma focused ion beam milling (FIB), followed by structural, compositional and electronic characterisation of Cr4Te5 using (scanning) transmission electron microscopy.

Your Key Tasks:

• Grow stoichiometric CrTex thin films using MBE, while varying the substrate temperature, flux ratios and growth rate.
• Establish and refine growth conditions that selectively stabilize the Cr4Te5 phase.
• Investigate the structural signatures and defect landscapes and their relevance to ferroelectric behavior.
• Characterize crystalline structure and phase purity using X-ray diffraction.
• Prepare samples for TEM using plasma FIB.
• Analyze the microstructure, interface sharpness and defect distributions using TEM.
• Correlate MBE growth parameters with phase stability, structural quality and ferroelectric-relevant properties.
  
  

Your Profile:

• You are studying physics, material science, engineering or a related subject at university and are looking for a topic for a Master`s thesis.
• You are interested in and ideally have previous knowledge of the fields of electron microscopy and solid state physics.
• You can work independently and responsibly and show commitment, a high level of teamwork and enjoyment of cooperative collaboration.
• You can quickly familiarize yourself with new methods and techniques.
• You are fluent in written and spoken English.
  
  

Our Offer:

We work on highly topical, innovative subjects and offer you the opportunity to actively shape change.

We offer you:

• An interesting, future-oriented and socially relevant topic for your thesis
• Ideal conditions for practical experience alongside your studies
• Interdisciplinary collaboration on projects in an international, committed and collegial team
• Excellent scientific equipment and the latest technology
• Qualified supervision by scientific colleagues
• Independent preparation and implementation of the assigned tasks
• A large research campus, which offers opportunities for networking with colleagues and for sporting activities alongside work
• Flexible working hours and appropriate remuneration

In addition to exciting tasks and a collegial working environment, we offer you much more: https://go.fzj.de/benefits

We welcome applications from people with diverse backgrounds, e.g. in terms of age, gender, disability, sexual orientation / identity, and social, ethnic and religious origin. A diverse and inclusive working environment with equal opportunities in which everyone can realize their potential is important to us.

The following links provide further information on diversity and equal opportunities: https://go.fzj.de/equality and on specific support options: https://go.fzj.de/womens-job-journey