能量色散X射线光谱学

Energy Dispersive X-ray Spectroscopy (EDS)

Energy Dispersive X-ray Spectroscopy (EDS) is a chemical analysis method that can be integrated with two primary electron beam techniques: Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Scanning Transmission Electron Microscopy (STEM).

When combined with these imaging tools, EDS provides spatially resolved elemental analysis from regions as small as 1 nanometer (STEM). In SEM, the analysis volume is larger, typically ranging between 0.1 to 3 micrometers. The interaction of the electron beam with the sample generates characteristic X-rays that are unique to the elements present. EDS analysis can be used to determine:

• Point-specific elemental composition

• Line scans for compositional profiles

• Elemental mapping of lateral distributions across the imaged area

Ideal Applications of EDS

• Elemental composition analysis of small areas using SEM/TEM imaging

• Defect identification and mapping

Our Strengths

• Rapid "first-look" compositional analysis

• Versatile, cost-effective, and widely accessible

• Quantitative capability for flat, polished, and homogeneous samples

Limitations

• Typically provides semi-quantitative analysis

• Sample must be compatible with SEM/TEM requirements

• Must be vacuum-compatible (not suitable for wet/organic materials)

• Analysis (and coating) may limit subsequent surface characterization

• Potential for elemental peak overlaps, requiring careful spectrum interpretation

EDS Technical Specifications

• Detected signal: Characteristic X-rays

• Detectable elements: Boron (B) to Uranium (U)

• Detection limit: 0.1–1 atomic % (at%)

• SEM sampling depth: 0.1–3 µm

• STEM sampling depth: ~0.1 µm (foil thickness-dependent)

• Imaging/mapping & line scans: Available

• Lateral resolution:

  • 1–2 nm for STEM-EDS

  • ≥0.1 µm for SEM-EDS