Multielemental chemical imaging using laser-induced breakdown spectrometry

Area of Science:

• Materials Science
• Analytical Chemistry
• Spectroscopy

Background:

• Silicon photovoltaic cells are crucial for renewable energy.
• Accurate chemical mapping is essential for quality control and performance optimization.
• Existing surface analysis techniques have limitations in sample size and material compatibility.

Purpose of the Study:

• To demonstrate the capability of multichannel laser-induced breakdown spectrometry (LIBS) for selective chemical imaging.
• To analyze the distribution of silver, titanium, and carbon in silicon photovoltaic cells.
• To report depth distributions of carbon impurities.

Main Methods:

• Utilized a 2.5 mJ pulsed nitrogen laser and a charge-coupled device spectrometer.
• Acquired LIBS spectra sequentially across the sample using a motorized x-y stage.
• Reconstructed 2D chemical images from spectral intensity profiles at specific wavelengths.

Main Results:

• Generated selective chemical images for silver, titanium, and carbon.
• Achieved a lateral resolution of 80 μm and a depth resolution better than 13 nm.
• Demonstrated room temperature and atmospheric pressure operation, enabling unlimited sample size and imaging of non-conductive materials.

Conclusions:

• Multichannel LIBS is a versatile technique for elemental imaging of silicon photovoltaic cells.
• The method offers significant advantages in terms of sample handling and material versatility.
• LIBS provides multielemental information from a single analysis, enhancing its utility in material characterization.