Tecnai tf 20 feg

The structural characteristics of the DBR were investigated using HRXRD (Philips, Panalytical X’pert, Cu Kα radiation), point-by-point-corrected SIMS, AFM, and TEM. The TEM samples were prepared using the in situ focused ion beam (FIB) lift-out technique on the FEI Helios 650 dual-beam FIB scanning electron microscope and were subsequently capped with a carbon layer followed by a locally capped protective Pt layer prior to milling. Images were collected using an FEI Tecnai TF-20 FEG transmission electron microscope operated at 200 kV. The reflectance spectra were measured at room temperature near normal incidence using a UV-vis spectrophotometer.

Further confirmation
of NP size distribution was attained by diameter measurement using
electron micrographs from a transmission electron microscope (TEM,
Tecnai G2, FEI). The TEM samples were made ready by drop-casting 2
μL of individual silver NPs in glycerol solution onto a Formvar–carbon-coated
400 mesh copper TEM grid (Agar Scientific, UK) at RT until being dried
and imaged on a FEI Tecnai TF20 FEG high-resolution TEM system, operating
at 200 kV. For the calibration of magnification as well as the scale
bar for TEM images, a standard cross-grating was used. For the calculation
of the average size and standard deviation of silver NPs, an image-processing
tool (Image J 1.50i) was used, with around 50 particles in the TEM
images.
Scanning-TEM-HAADF (high-angle annular dark-field) images
and STEM-energy-dispersive X-ray spectroscopy (STEM-EDS) spectrum
images were obtained with a Nion UltraSTEM 200-X instrument. The magnification
calibrations for the HAADF images were checked against the gold nanoparticle
lattice spacing. The EDS spectrum images were measured using EDX AMETEK,
with an active area of 30 mm, and analyzed with the TIA (TEM Imaging
and Analysis) software. The STEM-EDS maps are drawn with raw counts,
using the Cu peaks.