A new silicon drift detector for high spatial resolution STEM-XEDS: performance and applications

Area of Science:

• Materials Science
• Physics
• Analytical Chemistry

Background:

• Scanning transmission electron microscopy (STEM) is crucial for materials characterization.
• X-ray energy dispersive spectrometry (XEDS) provides elemental information.
• Existing XEDS detectors have limitations in count rate and low-energy sensitivity.

Purpose of the Study:

• To introduce a novel 100 mm2 silicon drift detector for aberration-corrected STEM.
• To evaluate the detector's performance, including count rate, low-energy sensitivity, and tilt dependence.
• To demonstrate the detector's utility in analyzing diverse materials.

Main Methods:

• Installation of a windowless silicon drift detector on an aberration-corrected STEM.
• Utilizing an ultra-high resolution pole piece without column modification.
• Performing X-ray energy dispersive spectrometry (XEDS) on various samples.

Main Results:

• Achieved a dramatic increase in XEDS count rate due to the windowless design and proximity to the sample.
• Demonstrated enhanced sensitivity to low-energy X-rays.
• Observed muted tilt dependence, simplifying sample positioning.
• Successfully analyzed AlxGa1-xN nanowires, perovskite oxides, and CdTe thin films.

Conclusions:

• The new silicon drift detector significantly advances XEDS capabilities in STEM.
• Its design overcomes limitations of conventional detectors, enabling more efficient and sensitive elemental analysis.
• The detector is versatile for analyzing a wide range of materials across different length scales and accelerating voltages.