This work was partly supported by Grants-in-Aid for Scientific Research on Kiban-kenkyu A (No. 26249096), Innovative Areas &#34;Nano Informatics&#34; (No. 25106004), and Wakate-kenkyu B (No. 26870271) from the Japan Society of the Promotion of Science.

1. Sample preprocess
<ol>
	<li>Thin film preparation for TEM
	<ol>
		<li>Prepare a sample for the present analysis method using standard transmission electron microscopy (TEM) sample preparation techniques, such as electropolishing for metal materials, ion milling for semiconductors or ceramics, typically less than 100-200 nm for HARECXS, uniformly flat over the area of ~1 &#956;m. Prepare thinner (50-100 nm) samples for HARECES in general.</li>
	</ol>
	</li>
	<li>Sample mounting to TEM
	<ol>
		<li>Mount the thin film prepared on a double-tilting TEM sample holder, followed by inserting the holder into a TEM equipped with a scanning mode and an EDX detector (Figure 1).</li>
	</ol>
	</li>
</ol>
2. TEM operation (specific to JEM2100 STEM with beam-rocking option attached)
<ol>
	<li>TEM alignment for beam-rocking
	<ol>
		<li>Start the TEM operation. After the routine TEM beam alignment procedure, go to STEM mode by checking Attachment Scanning Image Display (ASID) in the ASID window in the TEM control monitor (TCM,&#160;Figure 1 &#38; Figure 2).</li>
	</ol>
	</li>
	<li>Optical axis alignment
	<ol>
		<li>Click the Rocking button in the ASID window of the TCM and then click the Spot button in the Simple Image Viewer (SIV) to stop beam-rocking (Figure 2). Remove the sample from the field of view. Set the beam-rocking range smaller than &#177;2&#176; by clicking the Mag increment/decrement buttons.</li>
		<li>Turn the Brightness knob on left operation panel (LOP: Figure 3) clockwise to the limit, followed by turning the OBJ FOCUS COARSE knob of Right Operation Panel (ROP: Figure 3) counterclockwise to an underfocused condition: a caustic spot (Figure 4) appears on the fluorescent viewing screen.</li>
		<li>Press the BRIGHT TILT function key (LOP) and move the caustic spot to the center of the fluorescent screen using a pair of DEF/STIG X/Y knobs (L/ROP).</li>
		<li>Press the Standard Focus button (ROP), and then turn the BRIGHTNESS knob back counterclockwise so that an alternative caustic spot appears on the fluorescent screen.</li>
		<li>Press the F3 function key (ROP) (or click the Spot button in &#39;Alignment Panel for Maintenance&#39; window on TCM) and move the beam spot to the center using a pair of DEF/STIG X/Y knobs.</li>
		<li>Repeat steps 2.2.2-2.2.5 until the beam position stays at center even if the lens condition is switched at step 2.2.2 and 2.2.4.</li>
	</ol>
	</li>
	<li>Incident beam collimation and setting its pivot point
	<ol>
		<li>Introduce the third largest condenser aperture at the center of the optical axis by turning the aperture knob clockwise with its position manually adjusted with two attached screws (Figure 1). Then, adjust the condenser lens stigmator to correct the beam shape to be coaxially defocused by turning the BRIGHTNESS knob both ways, using a pair of DEF/STIG knobs with COND STIG key on.</li>
		<li>Press the HT WOBB key (ROP) and adjust the BRIGHT TILT knob to minimize the beam size fluctuation with the change in acceleration voltage. This process adjusts the beam convergence angle minimum. Press the HT WOBB key again to stop HT wobbler.</li>
		<li>Activate maintenance mode (consult the manufacturer&#39;s manual). Select JEOL from the menu bar &#8594; Scan/Focus window&#160;&#8594; Scan Control tab in TCM. Then, click the Cor button and click the Scan button instead of Spot in the Image control panel of SIV.</li>
		<li>To minimize the beam shift with beam-rocking, adjust a pair of DEF/STIG knobs, followed by turning the OBJ FOCUS FINE knob slightly counterclockwise. Finally, match the sample and pivot point height using Z control keys (ROP) so that the sample is focused on the fluorescent screen.</li>
	</ol>
	</li>
	<li>Final beam alignment to obtain electron-channeling pattern of sample
	<ol>
		<li>Move the sample area of interest back to the center, and start beam-rocking by clicking the Scan button in the SIV window. Manually turn clockwise the annular dark field (ADF) detector cylinder (Figure 1) and insert the detector.</li>
		<li>Set the ADF detector position at the center of the beam position by adjusting a pair of DEF/STIG knobs with PLA key on (LOP: Figure 3). Check the STEI-DF button in the Image Select menu of the ASID window and the STEM monitor in the SIV window displays an electron-channeling pattern (ECP). Adjust the Brightness/Contrast in the ASID window to best see ECP. Slightly turn the BRIGHTNESS knob to see the ECP contrast sharpest.</li>
	</ol>
	</li>
	<li>Data acquisition for HARECXS by EDX
	<ol>
		<li>By operating the STEM in beam-rocking mode, collect the EDX spectra by following the conventional spectral image method (using the spectral imaging function in Figure 5) as a function of beam tilting angles in the x and y directions and display elemental intensity distribution for specified elements, as shown in Figure 5. 
		NOTE: The intensity distribution pattern is called an ionization channeling pattern (ICP).</li>
		<li>Use the Line Scan function in Figure 5 for the 1D tilting measurement of a systematic row of reflections. Yellow arrow appears in the ECP preview to specify the measuring range, as shown in the upper left panel in Figure 5. Stop measurements when sufficient data statistics are obtained for ICPs.</li>
	</ol>
	</li>
</ol>
3. Data analysis for quantification
<ol>
	<li>Express X-ray intensity Ix for impurity x in the following form as a function of X-ray intensity Ii of host element i,12&#160; 
	<img alt="Equation 1" src="/files/ftp_upload/62015/62015eq01v2.jpg" /> 
	where 
	<img alt="Equation 2" src="/files/ftp_upload/62015/62015eq02v2.jpg" /> 
	NOTE: Here, fix is the fractional occupancy of impurity x on the type i host site, cx is the concentration of impurity x, and ni is the fractional concentration of the type i host element&#160;among the total host sites prior to the accommodation of impurity atoms of type x. ki is the k-factor of the type i host element. The additional constant offset &#946;x has been introduced as an extra fitted parameter to account for differences in interaction delocalization and errors in background subtractions. &#945;ix can be derived from Eq. (1) by multivariate linear regression for many sampling points of the ICP X-ray intensities.</li>
	<li>Derive cx and fix utilizing the condition&#160;&#931;ifix&#160;= 1 as12 
	<img alt="Equation 3" src="/files/ftp_upload/62015/62015eq03v2.jpg" /> 
	The uncertainties in cx and fix for multiple impurities are readily derived from the error propagation principle: 
	<img alt="Equation 4" src="/files/ftp_upload/62015/62015eq04v2.jpg" /> 
	and 
	<img alt="Equation 5" src="/files/ftp_upload/62015/62015eq05v2.jpg" /> 
	where&#160;&#948; &#945;ix is the statistical error obtained in the linear regression from Eq. (1).&#160;</li>
</ol>

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	<li>Rietveld, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+profile+refinement+method+for+nuclear+and+magnetic+structures.">A profile refinement method for nuclear and magnetic structures.</a> Journal of Applied Crystallography. 2, 65-71 (1969).</li><li>Izumi, F., Ikeda, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Rietveld-analysis+program+RIETAN-98+and+its+applications+to+zeolites.">A Rietveld-analysis program RIETAN-98 and its applications to zeolites.</a> Materials Science Forum. 321-324, 198-203 (2000).</li><li>Rose, H. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optics+of+high-performance+electron+microscopes.">Optics of high-performance electron microscopes.</a> Science and Technology of Advanced Materials. 9, 014107 (2008).</li><li>Muller, D. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atomic-scale+chemical+imaging+of+composition+and+bonding+by+aberration-+corrected+microscopy.">Atomic-scale chemical imaging of composition and bonding by aberration- corrected microscopy.</a> Science. 319, 1073-1076 (2008).</li><li>Spence, J. C. H., Taft&#248;, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ALCHEMI:+A+new+technique+for+locating+atoms+in+small+crystals.">ALCHEMI: A new technique for locating atoms in small crystals.</a> Journal of Microscopy. 130, 147-154 (1982).</li><li>Taft&#248;, J., Spence, J. C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crystal+site+location+of+iron+and+trace+elements+in+an+Mg-Fe+olivine+using+a+new+crystallographic+technique.">Crystal site location of iron and trace elements in an Mg-Fe olivine using a new crystallographic technique.</a> Science. 218, 49-51 (1982).</li><li>Yasuda, K., Yamamoto, T., Matsumura, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+atomic+structure+of+disordered+ion+tracks+in+magnesium+aluminate+spinel.">The atomic structure of disordered ion tracks in magnesium aluminate spinel.</a> Journal of Microscopy. 59, 27 (2007).</li><li>Tatsumi, K., Muto, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Local+electronic+structure+analysis+by+site-selective+ELNES+using+electron+channeling+and+first-principles+calculations.">Local electronic structure analysis by site-selective ELNES using electron channeling and first-principles calculations.</a> Journal of Physics Condensed Matter. 21, 1-14 (2009).</li><li>Yamamoto, Y., Tatsumi, K., Muto, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Site-selective+electronic+structure+of+aluminum+in+oxide+ceramics+obtained+by+TEM-EELS+analysis+using+the+electron+standing-wave+method.">Site-selective electronic structure of aluminum in oxide ceramics obtained by TEM-EELS analysis using the electron standing-wave method.</a> Materials Transactions. 48, 2590-2594 (2007).</li><li>Tatsumi, K., Muto, S., Nishida, I., Rusz, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Site-specific+electronic+configurations+of+Fe+3d+states+by+energy+loss+by+channeled+electrons.">Site-specific electronic configurations of Fe 3d states by energy loss by channeled electrons.</a> Applied Physics Letters. 96, 201911 (2010).</li><li>Tatsumi, K., Muto, S., Rusz, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Energy+loss+by+channeled+electrons:+A+quantitative+study+on+transition+metal+oxides.">Energy loss by channeled electrons: A quantitative study on transition metal oxides.</a> Microscopy and Microanalysis. 19, 1586-1594 (2013).</li><li>Muto, S., Ohtsuka, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-precision+quantitative+atomic-site-analysis+of+functional+dopants+in+crystalline+materials+by+electron-channelling-enhanced+microanalysis.">High-precision quantitative atomic-site-analysis of functional dopants in crystalline materials by electron-channelling-enhanced microanalysis.</a> Progress in Crystal Growth and Characterization of Materials. 63, 40-61 (2017).</li><li>Yamamoto, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+analysis+of+cation+mixing+and+local+valence+states+in+LiNixMn2-xO4+using+concurrent+HARECXS+and+HARECES+measurements.">Quantitative analysis of cation mixing and local valence states in LiNixMn2-xO4 using concurrent HARECXS and HARECES measurements.</a> Microscopy. 65, 253-262 (2016).</li><li>Ohtsuka, M., Muto, S., Tatsumi, K., Kobayashi, Y., Kawata, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+determination+of+occupation+sites+of+trace+Co+substituted+for+multiple+statistical+beam-rocking+TEM-EDXS+analysis.">Quantitative determination of occupation sites of trace Co substituted for multiple statistical beam-rocking TEM-EDXS analysis.</a> Microscopy. 65, 127-137 (2016).</li><li>Ohtsuka, M., Oda, K., Tanaka, M., Kitaoka, S., Muto, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=2D-HARECXS+analysis+of+dopant+and+oxygen+vacancy+sites+in+Al-doped+yttrium+titanate.">2D-HARECXS analysis of dopant and oxygen vacancy sites in Al-doped yttrium titanate.</a> J. Amer. Ceram. Soc. , (2021).</li><li>. QED for DigitalMicrograph Available from: <a target="_blank" href="https://www.hremresearch.com/Eng/plugin/QEDEng.html">https://www.hremresearch.com/Eng/plugin/QEDEng.html</a> (2020)</li></ol>

The authors have nothing to disclose.

Critical steps in the protocol are the ability to accurately align the incident rocking beam that has a small convergence angle with the pivot point, which is immobile at the specified area described in steps 2.2-2.3. A collimated incident beam with a convergence semi-angle of approximately no larger than 2 mrad was used. A beam size of 400 nm and diameter of 1 &#181;m can be selected by setting the condenser aperture #4 (10 &#956;m in diameter) and #3 (30 &#956;m) in the present hardware system.
The advantages of the present method are that (i) no advanced STEM instruments such as aberration-corrected STEM or even field emission electron gun is necessary; (ii) many sampling points (e.g., ~4,000 points for a scan area of 64 &#215; 64 pixels2) can be automatically collected with high efficiency, while operating the conventional STEM spectral imaging procedure on the analyzer side, and (iii) multiple spectroscopic methods such as EDX, EELS, and cathodoluminescence can be concurrently operated in a single integrated system, which enables multimodal analysis13.
Since the experimental ICPs can be precisely predicted by theoretical simulation, the method can be applied not only to cases where the crystal of interest contains multiple inequivalent atomic sites for a doped element14. Further extensions are ongoing, such as to detect the vacancy concentrations and associated displacements of host elements15, and even the ordering of dopants segregated along the grain boundaries of ceramics. The present method can provide a significant alternative technique applicable to relatively thick samples in contrast to atomic column-by-column analysis using aberration-corrected STEM, which requires the preparation of very thin high-quality samples (&#60; 10 nm).
Atom site-selective electronic state analysis using TEM-EELS (HARECES) rather than EDX is feasible8,9,10,11. For automatic measurement it is recommended to use &#39;ALCHEMI option&#39; in a beam controlling software &#39;QED,&#39; running on the Gatan Microscope Suite, supplied by HREM Research Inc16. In HARECES measurement, it is necessary to ensure that the transmitted beam is away from the EELS detector position and perpendicular to the systematic row in the beam tilting sequence8.
A limitation of this method is the minimum beam size of the incident electron beam, which limits the minimum measured area to approximately 400 nm. This is due to the aberration of the TEM lens system wherein the pivot center moves farther than the beam radius for a smaller beam size, which could be amended in the future by modifying the TEM deflector lens current setting to compensate for the beam wandering.
If the microscope used does not have beam-rocking mode, a very similar operation is achieved using QED software, which also addresses the limitation, as the software can rectify the pivot point moving even in the nano-beam mode. For S/TEMs manufactured by FEI Company (now part of Thermo Fisher Scientific), TIA scripting, open-source code can manage all S/TEM functions and attached detectors via a PC. Sequential EDX/EELS data acquisitions with successive incident beam tilting were performed using the scripting program TIA running on the TEM imaging and analysis platform13.

With the demand of downsizing most current industrial products, it is getting more and more important to understand the physical/chemical properties of materials from the microscopic perspective, sometimes in terms of atomic-scale spatial/electronic structures. Novel properties are often discovered unexpectedly when synthesizing materials by trial and error, selecting different numbers or kinds of elements, although current measurement techniques and ab initio theoretical calculations based on density functional theory have enabled design of novel materials with improved properties without time-consuming trial and error experiments. For example, some of the host atoms are substituted with other elements that can possibly improve the target property as results of either experimental or theoretical considerations. In this context, an important component of experimental information is brought about from detailed knowledge of the position of each constituent in the atomic structure of the material.
X-ray and/or neutron diffraction methods are conventionally and widely used not only because the structural analysis based on Rietveld analysis1,2 techniques has been well established and open to the public, but also owing to the development of high-flux X-ray sources (e.g., synchrotron radiation facilities) and modern neutron sources, which are easily accessible to general researchers. However, these techniques require samples with homogeneous structures, and they also require the Rietveld fit between the experimental and theoretical sets of diffracted peak intensities using structural factors. It can thus be difficult to distinguish between different elements if their structural factors are close to each other, such as in X-ray diffraction of neighboring elements in the periodic table.
In most current advanced materials, the compositions, precipitates, grain size, and impurities are adjusted and optimized to maximize the desired role at the nanometer scale. This means that these materials require characterization at the nanometer scale or even sub-nanometer scale to investigate whether they are synthesized as designed. In this context, it could be best achieved using transmission electron microscopy (TEM) and related analytical techniques.
The recent dramatic development of scanning TEM (STEM) in these decades, particularly based on aberration correction technologies, has accelerated a state-of-the-art technique to reveal the structure of a material and its elemental distribution at an atomic scale3,4. This method, however, requires precisely setting the crystalline material parallel to a low-order zone axis and to the extreme stability of the instrument during the measurement, which is a drawback. Hence, we demonstrate an alternative method that requires no such limitations, aberration&#160;correction, or even field emission electron gun.
Electron channeling in a crystalline material occurs if an incident electron beam propagates along particular atomic planes or columns, which depends on the direction of the incident high-energy electron beam with respect to the crystal axes, where an appropriate set of Bragg reflections and the excitation error of each reflection in a TEM are selected. The site-specific energy-dispersive X-ray (EDX or sometimes conventionally EDS) analysis technique that uses electron channeling is called the atom location by channeled electron microanalysis (ALCHEMI) method to evaluate the occupancies of host atomic sites by impurities5,6. This method has been extended to a more complex and quantitatively reliable approach, called high-angular-resolution electron-channeling X-ray spectroscopy (HARECXS), to determine impurity/dopant occupancies. This is realized by comparing the experimental beam-rocking curves with theoretical simulations7. This technique is further extended to high-angular-resolution electron-channeling electron spectroscopy (HARECES), which records electron energy loss spectra (EELS) instead of EDX8. This provides information on the site-specific local chemical states of a given element in different atomic environments9,10,11. In cases where each host element occupies a single crystallographic site, a simple linear regression and application of several formulae to the experimental dataset quantitatively determines the site occupancies of doped impurities without any theoretical simulations.
In the following sections, we provide detailed procedures of the method specific to the Jeol JEM2100 STEM system because it is explicitly equipped with the beam-rocking mode in the STEM operation menu. For users of other microscopes, please refer to the descriptions in the final paragraph of the Discussion section of this article.

<table><tbody><tr><td>Electron Energy-Loss Spectrometer</td><td>Gatan Inc.</td><td>Enfina1000</td><td>Parallel EELS detector</td></tr><tr><td>Energy dispersive X-ray detector</td><td>JEOL Ltd.</td><td>SD30GV</td><td>EDS silicon drift detector</td></tr><tr><td>Gatan Microscope Suite (GMS)</td><td>Gatan Inc.</td><td>ver. 2.3.</td><td>Integrated software platform for controling cameras, detectors, S/TEM and data analysis</td></tr><tr><td>QED</td><td>HREM Research Inc.</td><td>for GMS 2.3 32bit</td><td>beam controlling software, running on the Gatan Microscope Suite</td></tr><tr><td>scanning transmission electron microscope</td><td>JEOL Ltd.</td><td>JEM-2100</td><td>Beam-rocking mode option in ASID controlling window</td></tr><tr><td>TEMCON</td><td>JEOL Ltd.</td><td></td><td>Control software for JEM 2100</td></tr><tr><td>Thermo NSS software</td><td>Thermo Fischer Scientific Inc., USA</td><td></td><td>EDS control software</td></tr></tbody></table>

quantitative atomic-site analysis of functional dopants/point defects in crystalline materials by electron-channeling-enhanced microanalysis

A novel elemental and chemical analysis scheme based on electron-channeling phenomena in crystalline materials is introduced, where the incident high-energy electron beam is rocked with the submicrometric pivot point fixed on a specimen. This method enables us to quantitatively derive the site occupancies and site-dependent chemical information of impurities or intentionally doped functional elements in a specimen, using energy-dispersive X-ray spectroscopy and electron energy-loss spectroscopy attached to a scanning transmission electron microscope, which is of significant interest to current materials science, particularly related to nanotechnologies. This scheme is applicable to any combination of elements even when the conventional Rietveld analysis by X-ray or neutron diffraction occasionally fails to provide the desired results because of limited sample sizes and close scattering factors of neighboring elements in the periodic table. In this methodological article, we demonstrate the basic experimental procedure and analysis method of the present beam-rocking microanalysis.

The experimental ECP for BaTiO3 and ICPs of Ba-L, Ti-K&#945;, and O-K&#945; near the [100] and [110] zone axes are shown in Figure 6A and Figure 6B, respectively. Each constituent element exhibits a specific ICP, indicating that the ICP is atomic site-specific12.
As a fundamental application example, we examined Eu3+-doped Ca2SnO4, which exhibits strong red emission derived from the 5D0-7F2 electric dipole transition of trivalent Eu ions (Eu3+). Considering the ionic radii similarity criterion, it would be more relevant to assume that Eu3+ occupies the Ca2+ sites because Eu3+ is significantly close in size to Ca2+ than to Sn4+. However, Rietveld analysis of powder X-ray diffraction data revealed that Eu3+ equally occupied the Ca2+ and Sn4+ sites, presumably because the local charge neutrality criterion dominates in this case. An Eu and Y co-doped sample Ca1.8Y0.2Eu0.2Sn0.8O4 was then synthesized because Y3+ ions with a smaller ionic radius preferentially occupy smaller cation (Sn4+) sites, expelling larger Eu3+ ions out of the Sn4+ site into the larger Ca2+ site without changing the charge balance. As expected, Ca1.8Y0.2Eu0.2Sn0.8O4 exhibited a stronger emission than the Ca1.9Eu0.2Sn0.9O4 sample. The stronger red emission in the co-doped sample is explained by the increased fraction of Eu3+ ions occupying the asymmetric Ca site, coordinated by seven oxygen atoms, which enhances the electric dipole moment compared to that of the symmetric six-coordinated Sn site.
A series of Eu and Y co-doped polycrystalline samples with nominal compositions of Ca1.9Eu0.2Sn0.9O4 and Ca1.8Eu0.2Y0.2Sn0.8O4 were prepared, and the site occupancies of the dopants were determined by the present method.
Figure 7&#160;shows the ECP and ICPs of Ca-K, Sn-L, O-K, Eu-L, and Y-L for the Ca1.8Eu0.2Y0.2Sn0.8O4 sample near the [100] zone. The Eu-L ICP was closer to the Ca-K ICP, whereas the Y-L ICP was closer to Sn-L ICP. This suggests that the Eu and Y occupation sites could be biased, as expected. The coefficients, &#945;ix for i = Ca, Sn, and x = Eu, Y derived using Eq. (1), where nCa = 2/3 and nSn = 1/3. The k-factors of the constituent elements are calibrated in advance using a reference material with a known composition, the detailed discussion of which is found in ref.12. The site occupancies fix (Eq. (3)) of the impurities, and the impurity concentrations c of all the samples are tabulated in Table 1.
In Ca1.9Eu0.2Sn0.9O4, Eu3+ occupied the Ca2+ and Sn4+ sites equally, consistent with the results of the XRD-Rietveld analysis. In contrast, Eu3+ and Y3+ occupied the Ca2+ and Sn4+ sites at ratios of approximately 7:3 and 4:6, respectively, in the co-doped samples, significantly biased as expected, but also maintaining the charge neutrality condition within the present experimental accuracies12.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/62015/62015fig01.jpg" /> 
Figure 1: Instrumental outlook. Jeol JEM2100 STEM and its associated monitors, detectors, and operation panel configurations. <a href="https://www.jove.com/files/ftp_upload/62015/62015fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/62015/62015fig2v2.jpg" /> 
Figure 2: Layout of TEM control monitor (TCM). Control windows necessary for the present method are displayed and key functions and buttons are labeled. <a href="https://www.jove.com/files/ftp_upload/62015/62015fig2v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/62015/62015fig3v2.jpg" /> 
Figure 3: Left/right operation panels of the S/TEM. (Left) Left operation panel (LOP). (Right) Right operation panel. The function keys and operation knobs necessary for the present method are labeled. <a href="https://www.jove.com/files/ftp_upload/62015/62015fig3v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/62015/62015fig04.jpg" /> 
Figure 4: Caustic spot image on the fluorescent screen. The diameter of the spot ranges a few centimeters on the screen, depending on the defocus value. <a href="https://www.jove.com/files/ftp_upload/62015/62015fig04large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/62015/62015fig05.jpg" /> 
Figure 5: Appearance of EDS&#160;control monitor. Electron-channeling pattern (ECP) preview in upper left panel specifies the area of measurement. For 1D tilting measurements, X-ray Linescan is selected in the leftmost panel and the range of measurement is indicated by the yellow arrow in the ECP preview. Periodic table in the lower left panel selects the elements of the ionization channeling patterns (ICPs) to be displayed in upper right panel. Lower right panel displays the accumulated EDS&#160;pattern in real-time. <a href="https://www.jove.com/files/ftp_upload/62015/62015fig05large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/62015/62015fig06.jpg" /> 
Figure 6: Experimental ECPs and ICPs. (A: from left to right) ECP and ICPs of Ba-L, T-Ka, and O-Ka emissions from BaTiO3 obtained by beam-rocking near [100] zone axis. (B: from left to right) Same as (A) near [110] zone axes. This figure has been modified from [12]. <a href="https://www.jove.com/files/ftp_upload/62015/62015fig06large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/62015/62015fig07.jpg" /> 
Figure 7. ECP and corresponding X-ray ICPs from Ca1.8Eu0.2Y0.2Sn0.8O4 by beam-rocking near the [100] zone axis. (A) ECP. (B-F) ICPs of Ca-Ka, Sn-L, O-Ka, O-Ka, Eu-L, and Y-L emissions, respectively. This figure has been modified from [12]. <a href="https://www.jove.com/files/ftp_upload/62015/62015fig07large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<table border="1" fo:font-size="7px" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Sample</td>
			<td>Dopant</td>
			<td>&#945;Ca</td>
			<td>&#945;Sn</td>
			<td>fCa</td>
			<td>fSn</td>
			<td>c&#160;x (x = Eu or Y)</td>
		</tr>
		<tr>
			<td>Ca1.9Eu0.2Sn0.9O4</td>
			<td>Eu</td>
			<td>1.71&#177;0.001</td>
			<td>0.083&#177;0.001</td>
			<td>0.57&#177;0.001</td>
			<td>0.43&#177;0.002</td>
			<td>0.061&#177;0.001</td>
		</tr>
		<tr>
			<td rowspan="2">Ca1.8Eu0.2Y0.2Sn0.8O4</td>
			<td>Eu</td>
			<td>0.162&#177;0.001</td>
			<td>0.077&#177;0.001</td>
			<td>0.78&#177;0.003</td>
			<td>0.22&#177;0.008</td>
			<td>0.088&#177;0.006</td>
		</tr>
		<tr>
			<td>Y</td>
			<td>0.040&#177;0.002</td>
			<td>0.265&#177;0.009</td>
			<td>0.28&#177;0.002</td>
			<td>0.72&#177;0.001</td>
			<td>0.118&#177;0.004</td>
		</tr>
	</tbody>
</table>
Table 1. Derived parameters (defined in text) of the samples of Ca2-xEuxSn1-yYyO4 where (x, y) = (0.2, 0.0) and (0.2, 0.2).

Watch this Scientific Journal Video about Quantitative Atomic-Site Analysis of Functional Dopants/Point Defects in Crystalline Materials by Electron-Channeling-Enhanced Microanalysis at JoVE.com

Quantitative Atomic-Site Analysis of Functional Dopants/Point Defects in Crystalline Materials by Electron-Channeling-Enhanced Microanalysis

We provide a general outline of quantitative microanalysis methods for estimating the site occupancies of impurities and their chemical states by taking advantage of electron-channeling phenomena under incident electron beam-rocking conditions, which reliably extract information from minority species, light elements, oxygen vacancies, and other point/line/planar defects.

A novel elemental and chemical analysis scheme based on electron-channeling phenomena in crystalline materials is introduced, where the incident ...

quantitative-atomic-site-analysis-functional-dopantspoint-defects

Research

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Chemistry

5.8K Views.  Nagoya University. Dit nieuwe elementaire en chemische analyseschema kan worden gebruikt om locatieafhankelijke informatie voor onzuiverheden of dopants in een monster kwantitatief af te leiden met behulp van energiedispersieve röntgen- en elektronenenergieverliesspectroscopieën. De techniek is eenvoudig, goedkoop en kwantitatief betrouwbaar in vergelijking met andere analytische technieken die momenteel beschikbaar zijn en vereist geen state-of-the-art apparatuur. Deze methode is breed toepasbaar op niet all...

Video: Quantitative Atomic-Site Analysis of Functional Dopants/Point Defects in Crystalline Materials by Electron-Channeling-Enhanced Microanalysis

Electron Channeling Contrast Imaging for Rapid III-V Heteroepitaxial Characterization

Misfit dislocations in heteroepitaxial layers of GaP grown on Si(001) substrates are characterized through use of electron channeling contrast imaging (ECCI) in a scanning electron microscope (SEM). ECCI allows for imaging of defects and crystallographic features under specific diffraction conditions, similar to that possible via plan-view transmission electron microscopy (PV-TEM). A particular advantage of the ECCI technique is that it requires little to no sample preparation, and indeed can use large area, as-produced samples, making it a considerably higher throughput characterization method than TEM. Similar to TEM, different diffraction conditions can be obtained with ECCI by tilting and rotating the sample in the SEM. This capability enables the selective imaging of specific defects, such as misfit dislocations at the GaP/Si interface, with high contrast levels, which are determined by the standard invisibility criteria. An example application of this technique is described wherein ECCI imaging is used to determine the critical thickness for dislocation nucleation for GaP-on-Si by imaging a range of samples with various GaP epilayer thicknesses. Examples of ECCI micrographs of additional defect types, including threading dislocations and a stacking fault, are provided as demonstration of its broad, TEM-like applicability. Ultimately, the combination of TEM-like capabilities &#8211; high spatial resolution and richness of microstructural data &#8211; with the convenience and speed of SEM, position ECCI as a powerful tool for the rapid characterization of crystalline materials.

The use of electron channeling contrast imaging in a scanning electron microscope to characterize defects in III-V/Si heteroexpitaxial thin films is described. This method yields similar results to plan-view transmission electron microscopy, but in significantly less time due to lack of required sample preparation.

Misfit dislocations in heteroepitaxial layers of GaP grown on Si(001) substrates are characterized through use of electron channeling contrast imaging ...

Engineering

Biochemical and Structural Characterization of the Carbohydrate Transport Substrate-binding-protein SP0092

Development of new antimicrobials and vaccines for Streptococcus pneumoniae (pneumococcus) are necessary to halt the rapid rise in multiple resistant strains. Carbohydrate substrate binding proteins (SBPs) represent viable targets for the development of protein-based vaccines and new antimicrobials because of their extracellular localization and the centrality of carbohydrate import for pneumococcal metabolism, respectively. Described here is a rationalized integrated protocol to carry out a comprehensive characterization of SP0092, which can be extended to other carbohydrate SBPs from the pneumococcus and other bacteria. This procedure can aid the structure-based design of inhibitors for this class of proteins. Presented in the first part of this manuscript are protocols for biochemical analysis by thermal shift assay, multi angle light scattering (MALS), and size exclusion chromatography (SEC), which optimize the stability and homogeneity of the sample directed to crystallization trials and so enhance the probability of success. The second part of this procedure describes the characterization of the SBP crystals using a tunable wavelength anomalous diffraction synchrotron beamline, and data collection protocols for measuring data that can be used to resolve the crystallized protein structure.

A streamlined protocol for performing an extensive biochemical and structural characterization of a carbohydrate substrate binding protein from Streptococcus pneumoniae is presented.

Development of new antimicrobials and vaccines for Streptococcus pneumoniae (pneumococcus) are necessary to halt the rapid rise in multiple resistant ...

Biochemistry

Assessment of Boron Doped Diamond Electrode Quality and Application to In Situ Modification of Local pH by Water Electrolysis

Boron doped diamond (BDD) electrodes have shown considerable promise as an electrode material where many of their reported properties such as extended solvent window, low background currents, corrosion resistance, etc., arise from the catalytically inert nature of the surface. However, if during the growth process, non-diamond-carbon (NDC) becomes incorporated into the electrode matrix, the electrochemical properties will change as the surface becomes more catalytically active. As such it is important that the electrochemist is aware of the quality and resulting key electrochemical properties of the BDD electrode prior to use. This paper describes a series of characterization steps, including Raman microscopy, capacitance, solvent window and redox electrochemistry, to ascertain whether the BDD electrode contains negligible NDC i.e. negligible sp2 carbon. One application is highlighted which takes advantage of the catalytically inert and corrosion resistant nature of an NDC-free surface i.e. stable and quantifiable local proton and hydroxide production due to water electrolysis at a BDD electrode. An approach to measuring the local pH change induced by water electrolysis using iridium oxide coated BDD electrodes is also described in detail.

Assessment of Boron Doped Diamond Electrode Quality and Application to In Situ Modification of Local pH by Water Electrolysis

A protocol is described for the characterization of the key electrochemical parameters of a boron doped diamond (BDD) electrode and subsequent application for in situ pH generation experiments.

Boron doped diamond (BDD) electrodes have shown considerable promise as an electrode material where many of their reported properties such as extended ...

Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications of semiconductor materials. However, it is still under debate how the defect structure determines the band structure, and therefore, the recombination behavior of electron-hole pairs responsible for the optical and electrical properties of the extended defects. The present paper is a survey of procedures for the spatially resolved investigation of structural and of physical properties of extended defects in semiconductor materials with a scanning electron microscope (SEM). Representative examples are given for crystalline silicon. The luminescence behavior of extended defects can be investigated by cathodoluminescence (CL) measurements. They are particularly valuable because spectrally and spatially resolved information can be obtained simultaneously. For silicon, with an indirect electronic band structure, CL measurements should be carried out at low temperatures down to 5 K due to the low fraction of radiative recombination processes in comparison to non-radiative transitions at room temperature. For the study of the electrical properties of extended defects, the electron beam induced current (EBIC) technique can be applied. The EBIC image reflects the local distribution of defects due to the increased charge-carrier recombination in their vicinity. The procedure for EBIC investigations is described for measurements at room temperature and at low temperatures. Internal strain fields arising from extended defects can be determined quantitatively by cross-correlation electron backscatter diffraction (ccEBSD). This method is challenging because of the necessary preparation of the sample surface and because of the quality of the diffraction patterns which are recorded during the mapping of the sample. The spatial resolution of the three experimental techniques is compared.

The optical, electrical, and structural properties of dislocations and of grain boundaries in semiconductor materials can be determined by experiments performed in a scanning electron microscope. Electron microscopy has been used to investigate cathodoluminescence, electron beam induced current, and diffraction of backscattered electrons.

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications ...

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. They offer new possibilities for the characterization of living systems and are particularly appropriate for detecting, localizing and quantifying the presence of metal oxide nanoparticles both in biological specimens and the environment. Indeed, these techniques all meet relevant requirements in terms of (i) sensitivity (from 1 up to 10 &#181;g.g-1 of dry mass), (ii) micrometer range spatial resolution, and (iii) multi-element detection. Given these characteristics, microbeam chemical element imaging can powerfully complement routine imaging techniques such as optical and fluorescence microscopy. This protocol describes how to perform a nuclear microprobe analysis on cultured cells (U2OS) exposed to titanium dioxide nanoparticles. Cells must grow on and be exposed directly in a specially designed sample holder used on the optical microscope and in the nuclear microprobe analysis stages. Plunge-freeze cryogenic fixation of the samples preserves both the cellular organization and the chemical element distribution. Simultaneous nuclear microprobe analysis (scanning transmission ion microscopy, Rutherford backscattering spectrometry and particle induced X-ray emission) performed on the sample provides information about the cellular density, the local distribution of the chemical elements, as well as the cellular content of nanoparticles. There is a growing need for such analytical tools within biology, especially in the emerging context of Nanotoxicology and Nanomedicine for which our comprehension of the interactions between nanoparticles and biological samples must be deepened. In particular, as nuclear microprobe analysis does not require nanoparticles to be labelled, nanoparticle abundances are quantifiable down to the individual cell level in a cell population, independently of their surface state.

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

We describe a procedure for the detection of chemical elements present in situ in human cells as well as their in vitro quantification. The method is well-suited to any cell type and is particularly useful for quantitative chemical analyses in single cells following in vitro metal oxide nanoparticles exposure.

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. ...

All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics

The miniaturization of semiconductor devices to scales where small numbers of dopants can control device properties requires the development of new techniques capable of characterizing their dynamics. Investigating single dopants requires sub-nanometer spatial resolution, which motivates the use of scanning tunneling microscopy (STM). However, conventional STM is limited to millisecond temporal resolution. Several methods have been developed to overcome this shortcoming, including all-electronic time-resolved STM, which is used in this study to examine dopant dynamics in silicon with nanosecond resolution. The methods presented here are widely accessible and allow for local measurement of a wide variety of dynamics at the atomic scale. A novel time-resolved scanning tunneling spectroscopy technique is presented and used to efficiently search for dynamics.

We demonstrate an all-electronic method to observe nanosecond-resolved charge dynamics of dopant atoms in silicon with a scanning tunneling microscope.

The miniaturization of semiconductor devices to scales where small numbers of dopants can control device properties requires the development of new ...

Processing of Bulk Nanocrystalline Metals at the US Army Research Laboratory

Given their potential for significant property improvements relative to their large grained counterparts, much work has been devoted to the continued development of nanocrystalline metals. Despite these efforts, the transition of these materials from the lab bench to actual applications has been blocked by the inability to produce large scale parts that retain the desired nanocrystalline microstructures. Following the development of a method proven to stabilize the nanosized grain structure to temperatures approaching that of the melting point for the given metal, the US Army Research Laboratory (ARL) has progressed to the next stage in the development of these materials - namely the production of large scale parts suitable for testing and evaluation in a range of relevant test environments. This report provides a broad overview of the ongoing efforts in the processing, characterization, and consolidation of these materials at ARL. In particular, focus is placed on the methodology used for producing the nanocrystalline metal powders, in both small and large-scale amounts, that are at the center of ongoing research efforts.

This paper provides a brief overview of the ongoing efforts at the Army Research Laboratory on the processing of bulk nanocrystalline metals with an emphasis on the methodologies used for the production of the novel metal powders.

Given their potential for significant property improvements relative to their large grained counterparts, much work has been devoted to the continued ...

Atomic Layer Deposition of Vanadium Dioxide and a Temperature-dependent Optical Model

Vanadium dioxide is a material that has a reversible metal-insulator phase change near 68 &#176;C. To grow VO2 on a wide variety of substrates, with wafer-scale uniformity and angstrom level control of thickness, the method of atomic-layer deposition was chosen. This ALD process enables high-quality, low-temperature (&#8804;150 &#176;C) growth of ultrathin films (100-1000 &#197;) of VO2. For this demonstration, the VO2 films were grown on sapphire substrates. This low temperature growth technique produces mostly amorphous VO2 films. A subsequent anneal in an ultra-high vacuum chamber with a pressure of 7x10-4 Pa of ultra-high purity (99.999%) oxygen produced oriented, polycrystalline VO2 films. The crystallinity, phase, and strain of the VO2 were determined by Raman spectroscopy and X-ray diffraction, while the stoichiometry and impurity levels were determined by X-ray photoelectron spectroscopy, and finally the morphology was determined by atomic force microscopy. These data demonstrate the high-quality of the films grown by this technique. A model was created to fit to the data for VO2 in its metallic and insulating phases in the near infrared spectral region. The permittivity and refractive index of the ALD VO2 agreed well with the other fabrication methods in its insulating phase, but showed a difference in its metallic state. Finally, the analysis of the films&#39; optical properties enabled the creation of a wavelength- and temperature-dependent model of the complex optical refractive index for developing VO2 as a tunable refractive index material.

Thin films (100-1000 &#197;) of vanadium dioxide (VO2) were created by atomic-layer deposition (ALD) on sapphire substrates. Following this, the optical properties were characterized through the metal-insulator transition of VO2. From the measured optical properties, a model was created to describe the tunable refractive index of VO2.

Vanadium dioxide is a material that has a reversible metal-insulator phase change near 68 &#176;C. To grow VO2 on a wide variety of substrates, with ...

Synchrotron X-ray Microdiffraction and Fluorescence Imaging of Mineral and Rock Samples

In this report, we describe a detailed procedure for acquiring and processing&#160;x-ray microfluorescence (&#956;XRF), and Laue and powder microdiffraction two-dimensional (2D) maps at beamline 12.3.2 of the Advanced Light Source (ALS), Lawrence Berkeley National Laboratory. Measurements can be performed on any sample that is less than 10 cm x 10 cm x 5 cm, with a flat exposed surface. The experimental geometry is calibrated using standard materials (elemental standards for XRF, and crystalline samples such as Si, quartz, or Al2O3 for diffraction). Samples are aligned to the focal point of the x-ray microbeam, and raster scans are performed, where each pixel of a map corresponds to one measurement, e.g., one XRF spectrum or one diffraction pattern. The data are then processed using the in-house developed software XMAS, which outputs text files, where each row corresponds to a pixel position. Representative data from moissanite and an olive snail shell are presented to demonstrate data quality, collection, and analysis strategies.

We describe a beamline setup meant to carry out rapid two-dimensional x-ray fluorescence and x-ray microdiffraction mapping of single crystal or powder samples using either Laue (polychromatic radiation) or powder (monochromatic radiation) diffraction. The resulting maps give information about strain, orientation, phase distribution, and plastic deformation.

In this report, we describe a detailed procedure for acquiring and processing&#160;x-ray microfluorescence (&#956;XRF), and Laue and powder ...

Fabrication of a Dipole-assisted Solid Phase Extraction Microchip for Trace Metal Analysis in Water Samples

This paper describes a fabrication protocol for a dipole-assisted solid phase extraction (SPE) microchip available for trace metal analysis in water samples. A brief overview of the evolution of chip-based SPE techniques is provided. This is followed by an introduction to specific polymeric materials and their role in SPE. To develop an innovative dipole-assisted SPE technique, a chlorine (Cl)-containing SPE functionality was implanted into a poly(methyl methacrylate) (PMMA) microchip. Herein, diverse analytical techniques including contact angle analysis, Raman spectroscopic analysis, and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis were employed to validate the utility of the implantation protocol of the C-Cl moieties on the PMMA. The analytical results of the X-ray absorption near-edge structure (XANES) analysis also demonstrated the feasibility of the Cl-containing PMMA used as an extraction medium by virtue of the dipole-ion interactions between the highly electronegative C-Cl moieties and the positively charged metal ions.

The fabrication protocol of a dipole-assisted solid phase extraction microchip for the trace metal analysis is presented.

This paper describes a fabrication protocol for a dipole-assisted solid phase extraction (SPE) microchip available for trace metal analysis in water ...

Quantitative Atomic-Site Analysis of Functional Dopants/Point Defects in Crystalline Materials by Electron-Channeling-Enhanced Microanalysis

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