| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2018) | |
| Nanomaterials | Monday Sessions |
| Session NM-MoM |
| Session: | Nanocharacterization |
| Presenter: | Adam Hitchcock, McMaster University, Canada |
| Authors: | A. Hitchcock, McMaster University, Canada J. Wu, McMaster University, Canada X. Zhu, McMaster University, Canada D.A. Shapiro, Lawrence Berkeley National Laboratory J.R.I. Lee, Lawrence Livermore National Laboratory MM. Biener, Lawrence Livermore National Laboratory S.A. Gammon, Lawrence Livermore National Laboratory T.T. Li, Lawrence Livermore National Laboratory TF. Baumann, Lawrence Livermore National Laboratory |
| Correspondent: | Click to Email |
Highly porous materials with nanoscale functional coatings are of increasing technological interest in the areas of energy conversion and storage, catalysis, and sensing [1,2]. 3D nanocharacterization with explicit chemical speciation capability is important for their optimization. Here the new method of soft X-ray spectro-ptycho-tomography [3] is used to characterize Al2O3 aerogel samples coated with ZnO by atomic layer deposition (ALD). 4D imaging (chemical mapping in 3D by spectro-tomography) of an Al2O3 aerogel coated with ZnO by atomic layer deposition (ALD) was performed using both scanning transmission X-ray microscopy (STXM) and ptychography [4]. 2D and 3D spatial resolution was significantly increased by ptychography, relative to STXM. A 2D spatial resolution of 14 nm was achieved with ptychography while the spatial resolution of the 2D STXM maps was only 24 nm. The degree of ZnO coverage of the surface of the Al2O3 aerogel framework in 3 different samples was estimated and compared to the ALD targets. Quantitative analysis showed that the ZnO ALD coatings are non uniform. Comparisons are made to Electron microscopy imaging and X-ray fluorescence analysis results were performed, confirming the results. Other analyses of the 4D results, including 3D thickness distributions of each species and measurements of the degree of contact between Al2O3 and ZnO, were extracted from the reconstructed 3D data. Together the results provide useful feedback for optimization of the nanostructure of ALD coated alumina aerogels.
STXM performed using BL10ID1 at CLS and BL 5.3.2.2 at ALS . Ptychography performed using BL 11.0.2 and 5.3.2.1 at the ALS . Research supported by NSERC and the Department of Energy, Basic Energy Sciences under contracts DE-AC02-05CH11231 and DE-AC52-07NA27344. CLS is supported by the Canada Foundation for Innovation.
References
[1] J. Biener et al., Energy Environ. Sci.4 (2011) 656.
[2] M.M Biener et al., ACS Appl. Mater. Interfaces 5 (2013) 13129.
[3] Y. Yu et al., Nature Communications9 (2018) 921.
[4] A.P. Hitchcock, J. Electron Spectrosc. Rel. Phenom. 200 (2015) 49.