Measurement of specimen thickness and composition in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si20.gif" overflow="scroll"><mml:msub><mml:mrow><mml:mi>Al</mml:mi></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mi>Ga</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>-</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:mi mathvariant="normal">N</mml:mi><mml:mo>/</mml:mo><mml:mi>GaN</mml:mi></mml:math> using high-angle annular dark field imag

Rosenauer, A.; Gries, Katharina; Müller, Knut; Pretorius, A.; Schowalter, Marco; Avramescu, Adrian; Engl, Karl; Lutgen, S.

doi:10.1016/j.ultramic.2009.05.003

Cited by 171 publications

(74 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Here, both the theory will significantly be extended and realistic image simulations to accurately describe experimental images will be used [23][24][25][26] allowing us to demonstrate our method to technologically important materials.…”

mentioning

confidence: 99%

Optimal experimental design for the detection of light atoms from high-resolution scanning transmission electron microscopy images

Gonnissen

Backer

Dekker

et al. 2014

Applied Physics Letters

View full text Add to dashboard Cite

We report an innovative method to explore the optimal experimental settings to detect light atoms from scanning transmission electron microscopy (STEM) images. Since light elements play a key role in many technologically important materials, such as lithium-battery devices or hydrogen storage applications, much effort has been made to optimize the STEM technique in order to detect light elements. Therefore, classical performance criteria, such as contrast or signal-to-noise ratio, are often discussed hereby aiming at improvements of the direct visual interpretability. However, when images are interpreted quantitatively, one needs an alternative criterion, which we derive based on statistical detection theory. Using realistic simulations of technologically important materials, we demonstrate the benefits of the proposed method and compare the results with existing approaches. V C 2014 AIP Publishing LLC. [http://dx

show abstract

mentioning

confidence: 99%

Optimal experimental design for the detection of light atoms from high-resolution scanning transmission electron microscopy images

Gonnissen

Backer

Dekker

et al. 2014

Applied Physics Letters

View full text Add to dashboard Cite

show abstract

“…Proper settings were chosen to avoid beam damage and provide the best combination of signal-tonoise ratio, spatial and energy resolution. The results were simulated with the STEMSIM software package mimicking the experimental conditions [30][31][32][33]. Detailed experimental and simulation parameters can be found in the supplementary information [28].…”

mentioning

confidence: 99%

2D Atomic Mapping of Oxidation States in Transition Metal Oxides by Scanning Transmission Electron Microscopy and Electron Energy-Loss Spectroscopy

et al. 2011

View full text Add to dashboard Cite

Using a combination of high-angle annular dark-field scanning transmission electron microscopy and atomically resolved electron energy-loss spectroscopy in an aberration-corrected transmission electron microscope we demonstrate the possibility of 2D atom by atom valence mapping in the mixed valence compound Mn 3 O 4 . The Mn L 2;3 energy-loss near-edge structures from Mn 2þ and Mn 3þ cation sites are similar to those of MnO and Mn 2 O 3 references. Comparison with simulations shows that even though a local interpretation is valid here, intermixing of the inelastic signal plays a significant role. This type of experiment should be applicable to challenging topics in materials science, such as the investigation of charge ordering or single atom column oxidation states in, e.g., dislocations. DOI: 10.1103/PhysRevLett.107.107602 PACS numbers: 79.20.Uv, 68.37.Ma, 75.25.Dk In transition metal oxides, the oxidation state of the transition metal cations is of fundamental importance as the physical properties of many oxides are determined by the occupancy of the cation d bands. Multiferroicity, for example, can be driven by charge ordering of these cations, as in Fe 3 O 4 and Pr 1Àx Ca x MnO 3 [1-3]. However, the exact mechanism of multiferroic behavior is not fully understood to date. A method allowing for direct mapping of cation valence states in these materials at atomic resolution should therefore provide further insight into the origin of multiferroicity.Recently, atomic resolution elemental mapping has become feasible by means of spatially resolved electron energy-loss spectroscopy and energy dispersive x-ray spectroscopy in a scanning transmission electron microscope (STEM-EELS and STEM-EDX) [4][5][6][7][8][9]. At the same time, tremendous effort is being invested into the identification of the oxidation states of cations using electron energy-loss spectroscopy (EELS). The shape of the L 2;3 edge [10], the chemical shift [11,12] and the L 3 =L 2 ratio [13] have all been used as a fingerprint for the transition metal valence. In fact, the correlation between the energy-loss near-edge structure (ELNES) and valence in different transition metal oxides was confirmed by several experiments in literature [10,[14][15][16][17][18][19][20][21]. The higher the energy resolution, the more convincing this link between valence and ELNES features becomes. Combining the atomic resolution capabilities of a STEM with bonding and valence information from EELS is a highly attractive prospect. While bonding information has been obtained at atomic resolution [7,17,22], 2D oxidation state mapping at the atomic level in, e.g., metaloxide materials has remained challenging due to poor EELS signal-to-noise ratio and the need for simultaneous high spatial and energy resolution of the instrument [10,17,23].Mn 3 O 4 is known to be a mixed valence compound, containing both Mn 2þ and Mn 3þ ions at room temperature [24]. It has a spinel structure with lattice parameters a ¼ 5:762 A and c ¼ 9:4696 A and space group I41=amd. Many interesting...

show abstract

“…Static atomic displacements were taken into account and the simulations were carried out in dependence on specimen thickness and indium concentration ( figure 3). The specimen thickness is deduced by comparing the normalized intensities in regions of known concentration (GaN regions in this case) with the reference values for the according concentration (0% indium in this case) [7]. The specimen thickness is then interpolated over the regions of unknown concentration (figure 4).…”

Section: Specimen Thickness and Concentration Determinationmentioning

confidence: 99%

A (S)TEM and atom probe tomography study of InGaN

Mehrtens

Bley

Schowalter

et al. 2011

J. Phys.: Conf. Ser.

Self Cite

View full text Add to dashboard Cite

Abstract. In this work we show how the indium concentration in high indium content In x Ga 1-x N quantum wells, as they are commonly used in blue and green light emitting diodes, can be deduced from high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images. This method bases on introducing normalized intensities which can be compared with multislice simulations to determine the specimen thickness or the indium concentration. The evaluated concentrations are compared with atom probe tomography measurements. It is also demonstrated how the quality of focused ion beam prepared TEMlamellas can be improved by an additional etching with low energy ions.

show abstract

Measurement of specimen thickness and composition in AlxGa1-xN/GaN using high-angle annular dark field imag

Cited by 171 publications

References 19 publications

Optimal experimental design for the detection of light atoms from high-resolution scanning transmission electron microscopy images

Optimal experimental design for the detection of light atoms from high-resolution scanning transmission electron microscopy images

2D Atomic Mapping of Oxidation States in Transition Metal Oxides by Scanning Transmission Electron Microscopy and Electron Energy-Loss Spectroscopy

A (S)TEM and atom probe tomography study of InGaN

Contact Info

Product

Resources

About