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Ga-doped BiFeO3 thin films for brain-inspired computing

Available immediately (October 2019) to ambitious students in applied physics, nanotechnology, and chemical engineering.

Project motivation:

Bismuth ferrite (BiFeO3) is a lead-free ferroelectric material which can be grown in a variety of structural phases. Through chemical doping with gallium a tetragonal phase with large out-of-plane polarization can be stabilized, which is highly interesting for electronic applications.


Project goal:

We want to refine the currently existing phase diagram for epitaxially-grown, single-crystalline Ga:BiFeO3 thin films over a wide range of doping concentrations. Ideally, we will find an optimum doping concentration at which we can grow films in the tetragonal phase independently of the chosen substrate. Such films could be used to build artificial synapses in neuromorphic computing devices based on ferroelectric tunnel junctions.


Possible tasks of a MSc student:


  • Grow thin films by pulsed laser deposition (PLD).
  • Perform high resolution X-ray diffraction (XRD) at variable temperatures.
  • Verify the thin film stoichiometry by XPS, EDX, RBS, XRF.
  • Measure ferroelectric device properties such as P-E and C-V loops, retention, and fatigue.
  • Piezoelectric force microscopy (PFM).
  • Determine the band alignment (I-V, C-V, UPS, optical measurements).
  • If interested, students can get a professional cleanroom training and independently perform photolithography, metal electrode sputtering, and ion etching to fabricate demonstrator devices

Successful candidates can become co-author of a peer-reviewed publication. Preliminary data from a previous master students is already available.

Contact:

Ir. Yorick Birkhölzer, CR 3219, y.a.birkholzer@utwente.nl

Prof. dr. ir. Gertjan Koster, CR 3247, g.koster@utwente.nl

Inorganic Materials Science Group

https://www.utwente.nl/en/tnw/ims/