Metallic and semiconducting solid-state materials can readily be analyzed in APT. Insulating solid-state materials like ceramics or minerals can typically be analyzed but the data sets that can be acquired tend to be significantly smaller and contain notable errors.
APT is a destructive analysis technique, the tip-shaped sample gets taken apart atom-by-atom and hence destroyed during the analysis process. Typically, APT analysis end when the tip-shaped samples mechanically break.
Samples that are mechanically weak, for example heterostructures with weak adhesion or porous material are hence usually not suited for APT as they cannot withstand the mechanical stress. In addition, the material must be able to withstand the preparation process. The tip is usually formed using electron and ion-beams in a vacuum chamber, hence the material to be investigated should not change when exposed to either of the beams or vacuum.
Metallic and semiconducting solid-state materials can readily be analyzed in APT. Insulating solid-state materials like ceramics or minerals can typically be analyzed but the data sets that can be acquired tend to be significantly smaller and contain notable errors.
APT is a destructive analysis technique, the tip-shaped sample gets taken apart atom-by-atom and hence destroyed during the analysis process. Typically, APT analysis end when the tip-shaped samples mechanically break.
Samples that are mechanically weak, for example heterostructures with weak adhesion or porous material are hence usually not suited for APT as they cannot withstand the mechanical stress. In addition, the material must be able to withstand the preparation process. The tip is usually formed using electron and ion-beams in a vacuum chamber, hence the material to be investigated should not change when exposed to either of the beams or vacuum.
Metallic and semiconducting solid-state materials can readily be analyzed in APT. Insulating solid-state materials like ceramics or minerals can typically be analyzed but the data sets that can be acquired tend to be significantly smaller and contain notable errors.
APT is a destructive analysis technique, the tip-shaped sample gets taken apart atom-by-atom and hence destroyed during the analysis process. Typically, APT analysis end when the tip-shaped samples mechanically break.
Samples that are mechanically weak, for example heterostructures with weak adhesion or porous material are hence usually not suited for APT as they cannot withstand the mechanical stress. In addition, the material must be able to withstand the preparation process. The tip is usually formed using electron and ion-beams in a vacuum chamber, hence the material to be investigated should not change when exposed to either of the beams or vacuum.
Metallic and semiconducting solid-state materials can readily be analyzed in APT. Insulating solid-state materials like ceramics or minerals can typically be analyzed but the data sets that can be acquired tend to be significantly smaller and contain notable errors.
APT is a destructive analysis technique, the tip-shaped sample gets taken apart atom-by-atom and hence destroyed during the analysis process. Typically, APT analysis end when the tip-shaped samples mechanically break.
Samples that are mechanically weak, for example heterostructures with weak adhesion or porous material are hence usually not suited for APT as they cannot withstand the mechanical stress. In addition, the material must be able to withstand the preparation process. The tip is usually formed using electron and ion-beams in a vacuum chamber, hence the material to be investigated should not change when exposed to either of the beams or vacuum.
Metallic and semiconducting solid-state materials can readily be analyzed in APT. Insulating solid-state materials like ceramics or minerals can typically be analyzed but the data sets that can be acquired tend to be significantly smaller and may contain notable errors.
APT is a destructive analysis technique, the tip-shaped sample gets taken apart atom-by-atom and hence destroyed during the analysis process. Typically, APT analysis end when the tip-shaped samples mechanically break. Samples that are mechanically weak, for example heterostructures with weak adhesion or porous material are hence usually challenging to analyze in APT as they tend to rupture under the mechanical stress. In addition, the material must be able to withstand the preparation process. The tip is usually formed using electron and ion-beams in a vacuum chamber, hence the material to be investigated should not change when exposed to either of the beams or vacuum.
At PolyAPT we are committed to extend the applicability of APT to new materials for example by establishing cryo-preparation procedure and improve the usefulness of APT when applied to established materials by developing new algorithms to analyze APT data. We actively look to participate in joint projects that work towards these goals.
APT works on tip shaped samples with tip radii on the order of 50-150 nm. The tips can either be formed by electropolishing or Focused Ion Beam (FIB) milling. Electropolishing is mostly used for the preparation of metallic tips. Most other materials are prepared in a FIB/SEM Dual Beam.
A small piece of material is cut free using the FIB, lifted out from the sample using a micromanipulator, welded to the end of a tungsten wire using FIB or SEM-based deposition and then sharpened to a tip by annular milling with the FIB.
FIB based preparation allows for site-specific preparation. As a rule of thumb, features that can be seen in an SEM, can be prepared to be incorporated in a tip suitable for APT. Features that are either too small to be seen in a SEM or can’t be distinguished from their surrounding due to lack of contrast need to be marked before preparation.
For each detected ion the ion’s mass-to-charge ratio is determined and its 3D – x, y, z – position is estimated. The mass-to-charge ratio for all ions is plotted has a histogram commonly referred to as the mass spectrum. Peaks in the mass-spectrum are manually associated with elements.
The 3D positions of all detected ions are usually represented as a point-cloud where the elemental association of the ion is represented by a color.
The 3D point-cloud can be mapped onto a 3D grid by calculating the elemental concentrations in each bin of the grid. Images of the elemental distribution on the 3D-grid can then be extracted or iso-concentration surfaces can be calculated that highlight regions where a given element is high or low in concentration. The 3D point-cloud or parts of the 3D point-cloud can be reduced to 2D maps or 1D profiles of the elemental distribution along arbitrary directions by integrating over the respective perpendicular directions. Neighborhoods can be analyzed to reveal which elements cluster together and which elements disperse.
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