In thin film form, transition metal oxides can be subjected to intense electric fields and thermal gradients and are known to exhibit characteristic resistance changes, including resistive-, threshold- and complementary-switching behaviour that is well suited to applications such as nonvolatile memory, low power oxide electronics, bio- and environmental-sensing and neuromorphic computing.
Resistive switching is of particular interest for non-volatile memory applications as it involves a resistance change that can be reversibly switched between stable high- and low-resistance states by the application of suitable voltage pulses. It is now generally agreed that these resistance changes are the result of thermally enhanced, electric-stress driven structural changes resulting from defect generation/migration and associated chemical (Redox) processes. Moreover, the resistance change is believed to be confined to a filamentary conduction path just a few nanometres in diameter and is therefore largely independent of the film/device area. Due to the nonlinearly of the ion (defect) transport and the small volume of the active region, resistive switching can also be extremely fast (
This project will combine experimental work, computer simulation and modelling to investigate the physical processes underpinning resistive switching in transition metal oxides (e.g. Ta2O5, HfO2, Nb2O5 and NbO2) and to explore its application in future non-volatile memory (i.e. ReRAM) devices.
Through the project, the student will develop skills in the area(s) of:
- Nanotechnology, including nanoscale fabrication and nanoscale characterisation
- Advanced materials processing and characterisation
- Semiconductor clean-room technology
- Multiphysics modelling of complex physical phenomena
- Data acquisition, analysis and interpretation
- Critical thinking
- Scientific communication (oral and written)