Abstract
Measuring the diffusion of ions and vacancies at nanometer length scales is crucial to understanding fundamental mechanisms driving technologies as diverse as batteries, fuel cells, and memristors; yet such measurements remain extremely challenging. Here, we employ a multimodal scanning probe microscopy (SPM) technique to explore the interplay between electronic, elastic, and ionic processes via first-order reversal curve I-V measurements in conjunction with electrochemical strain microscopy (ESM). The technique is employed to investigate the diffusion of oxygen vacancies in model epitaxial nickel oxide (NiO) nanocrystals with resistive switching characteristics. Results indicate that opening of the ESM hysteresis loop is strongly correlated with changes to the resonant frequency, hinting that elastic changes stem from the motion of oxygen (or cation) vacancies in the probed volume of the SPM tip. These changes are further correlated to the current measured on each nanostructure, which shows a hysteresis loop opening at larger (∼2.5 V) voltage windows, suggesting the threshold field for vacancy migration. This study highlights the utility of local multimodal SPM in determining functional and chemical changes in nanoscale volumes in nanostructured NiO, with potential use to explore a wide variety of materials including phase-change memories and memristive devices in combination with site-correlated chemical imaging tools.
Original language | English |
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Pages (from-to) | 8387-8394 |
Number of pages | 8 |
Journal | ACS Nano |
Volume | 11 |
Issue number | 8 |
DOIs | |
State | Published - Aug 22 2017 |
Funding
The scanning probe microscopy studies were conducted at the Center for Nanophase Materials Sciences which also provided support (R.K.V., S.V.K.) and which is a U.S. DOE Office of Science User Facility.
Funders | Funder number |
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DOE Office of Science |
Keywords
- epitaxial
- first-order reversal curve
- nanocrystals
- nickel oxide
- resistive switching
- scanning probe microscopy