Fei quanta 650 sem

Scanning electron microscope (SEM) images were taken on Merlin field emission SEM (Zeiss, Thornwood, NY) and FEI Quanta 650 SEM (Thermo Fisher Scientific, Waltham, MA). Surface profiles along the diameter of the electrodes were obtained by Wyko NT9800 Optical Profilometer (Bruker Corporation, Billerica, MA) using Vertical shift interferometry (VSI) mode. A 50x optical lens was used and the sampling size was 96 nm. Cylinder tilt correction was applied.

Scanning electron microscope (SEM) images were taken on FEI Quanta 650 SEM (Thermo Fisher Scientific, Waltham, MA). Secondary electron detector was used at an accelerating voltage of 2.0 kV.
X-ray photoelectron spectrometer (Physical Electronics, Chanhassen, MN) was used to obtain elemental composition and bonding information. The Al Kα monochromatic X-ray source (1486.6 eV) was used with a pass energy of 224 eV for elemental composition and 55 eV for electronic state information. The XPS spectra were analyzed with MultiPak software, and the C1s peaks were fitted with sp2 C (283.7 eV), sp3 C (285.2 eV), C-O (287.0 eV), C=O (288.9 eV) and π-π* (291.1 eV) bonds.
Raman spectra was performed on Renishaw InVia Confocal Raman microscope (Renishaw, Hoffman Estates, IL) with 1800 lines/mm diffraction grating. A 514 nm laser was focused on the CFME samples through a 50x objective. Laser intensity was 50% and scan range was 100 cm^-1 to 3200 cm^-1.