Direct observation of conductive filament formation in Alq3 based organic resistive memories
| Authors | |
|---|---|
| Year of publication | 2015 |
| Type | Article in Periodical |
| Magazine / Source | Journal of Applied Physics |
| MU Faculty or unit | |
| Citation | |
| Web | http://scitation.aip.org/content/aip/journal/jap/118/7/10.1063/1.4928622 |
| Doi | http://dx.doi.org/10.1063/1.4928622 |
| Field | Solid matter physics and magnetism |
| Keywords | Silver; Alq3; diffusion; electrodes; negative resitance; hybrid organic-inorganic memories; resistive switching; metal nano-particles; filamentary conduction; X-ray reflectivity; XPS; ToF-SIMS |
| Description | This work explores resistive switching mechanisms in non-volatile organic memory devices based on tris(8-hydroxyquinolie) aluminum (Alq(3)). Advanced characterization tools are applied to investigate metal diffusion in ITO/Alq(3)/Ag memory device stacks leading to conductive filament formation. The morphology of Alq(3)/Ag layers as a function of the metal evaporation conditions is studied by X-ray reflectivity, while depth profile analysis with X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry is applied to characterize operational memory elements displaying reliable bistable current-voltage characteristics. 3D images of the distribution of silver inside the organic layer clearly point towards the existence of conductive filaments and allow for the identification of the initial filament formation and inactivation mechanisms during switching of the device. Initial filament formation is suggested to be driven by field assisted diffusion of silver from abundant structures formed during the top electrode evaporation, whereas thermochemical effects lead to local filament inactivation. |
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