Resistive switches, which are also known as memristors, are low-power, nanosecond-response devices that are used in a range of memory-centric technologies. Driven by an externally applied potential, the switching mechanism of valence change resistive memories involves the migration, accumulation and rearrangement of oxygen vacancies within a dielectric medium, leading to a change in electrical conductivity. The ability to look inside these devices and understand how morphological changes characterize their function has been vital in their development. However, current technologies are often destructive and invasive. Here, we report a non-destructive optical spectroscopy technique that can detect the motion of a few hundred oxygen vacancies with nanometre-scale sensitivity. Resistive switches are arranged in a nanoparticle-on-mirror geometry to exploit the high optical sensitivity to morphological changes occurring in tightly confined plasmonic hotspots within the switching material. Using this approach, we find that nanoscale oxygen bubbles form at the surface of a strontium titanate memristor film, leading ultimately to device breakdown on cycling.
|Number of pages||7|
|Early online date||5 Oct 2020|
|Publication status||Published - Nov 2020|
Bibliographical noteFunding Information:
G.D.M. acknowledges support from the Winton Programme for the Physics of Sustainability. J.J.B. acknowledges funding from EPSRC grant no. EP/L027151/1 and NanoDTC EP/L015978/1, and W.L. and J.M.-D. from EPSRC grants nos. EP/L011700/1, EP/N004272/1 and EP/P007767/1 and the Isaac Newton Trust. A.D. acknowledges support from a Royal Society University Research Fellowship URF/R1/180097 and Royal Society Research Fellows Enhancement Award RGF/EA/181038. B.d.N. acknowledges support from the Leverhulme Trust and the Isaac Newton Trust in the form of an ECF. The US–UK collaborative effort was funded by the US National Science Foundation (ECCS-1902644 (Purdue University) and ECCS-1902623 (University at Buffalo, SUNY)) and EPRSC grant no. EP/T012218/1. J.M.-D. also acknowledges funding from the UK Royal Academy of Engineering, grant no. CiET1819_24. B.Z. acknowledges support from the China Scholarship Council and Cambridge Commonwealth, European and International Trust.
© 2020, The Author(s), under exclusive licence to Springer Nature Limited.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering