Postdoc: Operando on chip investigation of failure in optical phase change materials using ultrafast X rays

Aarhus University, Department of Chemistry, Denmark, invites applications for a fully funded 2-year postdoctoral position starting 1 January 2027 or as soon as possible thereafter.

The goal of this project is to advance the understanding of failure mechanisms in optical phase change materials used in photonic devices, using synchrotron X-rays and X-ray free electron lasers (XFEL) .

Optical phase change materials can be reversibly switched between amorphous and crystalline states on fast timescales and are enabling materials for emerging photonic computing technologies. The postdoctoral researcher will perform operando and time-resolved structural characterization of materials and devices during switching, combining methods such as:

• Laser pump and X-ray probe total scattering
• WAXS and SAXS
• Imaging
• Femtosecond X-ray diffraction

These techniques will probe structure and dynamics in real time under device-relevant conditions . Target facilities include DESY, MAX IV, European XFEL, ESRF, APS, and LCLS , depending on awarded beamtime. The project is supported by the Independent Research Fund Denmark .

• Co-lead beamtime proposals and campaigns
• Work with existing on-chip photonic device platforms in collaboration with project partners
• Design and execute operando experiments to probe structural dynamics and degradation during repeated switching
• Analyze large scattering and diffraction datasets and connect structural signatures to device-level failure
• Contribute to beamtime proposals, experimental campaigns, and dissemination of results
• Publish in leading journals and present at international conferences

• PhD in chemistry, physics, materials science, or a related field
• Experience with synchrotron X-ray scattering and/or XFEL experiments
• Strong skills in crystallographic and scattering data analysis , including handling large datasets
• Solid understanding of crystallography, powder X-ray diffraction, diffuse scattering, phase transitions, and background modeling
• Programming skills (e.g., Python or similar)
• Experience with operando or time-resolved experiments, and X-ray instrumentation
• Ability to work independently with strong motivation and to collaborate in a team environment
• Fluent written and spoken English

Desirable:

• Experience with X-ray imaging

• A fully funded 2-year postdoctoral position at Aarhus University
• Strong access to international large-scale facility collaborations and experimental campaigns
• A project with substantial ownership , including first-author publication opportunities
• Structured mentorship aimed at developing an independent research profile, including support for proposal writing and leadership in experimental planning
• Freedom to develop a related side project aligned with personal research interests
• Support for international conference participation and possible research stays
• A collaborative environment across the Department of Chemistry, CENSEMAT Centre for Energy Materials, and the iMAT Center for Integrated Materials Research

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