Comparative study on the specimen thickness measurement using EELS and CBED methods

Abstract

Two thickness measurement methods using an electron energy loss spectroscopy (EELS) and 10a convergent beam electron diffraction (CBED) were compared in an Fe-18Mn-0.7C alloy. The thin foil specimen was firstly tilted to satisfy 10a two-beam condition. Low loss spectra of EELS and CBED patterns were acquired in scanning transmission electron microscopy (STEM) and TEM-CBED modes under the two-beam condition. The log-ratio method was used for measuring the thin foil thickness. Kossel-Möllenstedt (K-M) fringe of the diffracted disk of austenite was analyzed to evaluate the thickness. The results prove the good coherency between both methods in the thickness range of 72 ~ 113 nm with a difference of less than 5%.

In-situ transmission electron microscopy observation of the evolution of dislocation loops and gas bubbles in tungsten during H2+ and He+ dual-beam irradiation

“…Before irradiation, the thickness of in-situ monitored region was measured by convergent beam electron diffraction technique at 1173 K using the method in Ref. [41] and was approximately 135 nm. The average displacement damage rate, injected H concentration rate, and injected He concentration rate were calculated and approximately 3.94 × 10 -5 dpa•s −1 , 3.27×10 −6 s −1 , and 3.03×10 −6 s −1 , respectively.…”

Unveiling the charge transfer dynamics steered by built-in electric fields in BiOBr photocatalysts

“…5 , 6 ), which offers important insights into the carrier migration dynamics in BiOBr platelets. First, by using an electron energy loss spectroscopy (EELS) technique 59 – 61 , we revealed a weak correlation between charge dynamic and thickness for identical BiOBr-2.5 platelets, implying that a change in thickness of BiOBr platelets has little effect on the charge dynamic (Supplementary Figs. 11 – 13 ).…”

Evaluation of TEM methods for their signature of the number of layers in mono- and few-layer TMDs as exemplified by MoS2 and MoTe2

“…Transmission electron microscopy (TEM) is an indispensable tool for studying the structure of freestanding 2D TMDs and it would be of great advantage, if the number of layers could be directly determined in TEM experiments. Despite the broad spectrum of methods available within TEM, the determination of the number of layers is not a trivial task (Yang and Egerton, 1995;Pozsgai, 1997;Diebold et al, 2003;Heo, 2020;Gorelik et al, 2021b). Here we present a methodological study of the influence of the number of layers on data obtained using high-resolution imaging (HRTEM), electron energy-loss spectroscopy (EELS), and electron diffraction (ED).…”