Multielemental Chemical Imaging Using Laser-Induced Breakdown Spectrometry

Abstract

Multichannel laser-induced breakdown spectrometry (LIBS) is used to generate selective chemical images for silver, titanium, and carbon from silicon photovoltaic cells. A 2.5 mJ pulsed nitrogen laser and a spectrometer using charge-coupled device detection were employed. LIBS images were acquired sequentially by moving the sample located on a motorized x-y translational stage step by step while storing the multichannel LIBS spectrum for each position of the sample, followed by computer-based reconstruction of two-dimensional selective images from intensity profiles at several wavelengths. Depth distributions of carbon impurities are also reported. Room temperature and atmospheric pressure operation as used here remove the restrictions on sample size exhibited by other surface analysis techniques used for imaging applications. Thus, the sample size in LIBS imaging is in principle unlimited. A LIBS experiment does not require a sample to be conductive. Therefore, virtually all materials can be imaged. Although LIBS is a typical example of destructive analytical technique, multichannel detection as demonstrated here confers the possibility to LIBS of obtaining multielement information from a given surface area. Lateral resolution of 80 μm and depth resolution of better than 13 nm were observed. The ultimate limitation to imaging the first layer of the surface in LIBS is the spectral signal-to-noise ratio as dictated by the ablation threshold of the material.

Effect of surface topography in the characterization of stainless steel using laser-induced breakdown spectrometry

“…15,16 Rapid in situ analysis of worked material without sample preparation and micro-and macromapping over several centimetres by scanning the optical system or moving the sample on a translation stage are interesting capabilities of LIBS. 17,18 The sulphur content in steel was determined by the LIBS method. 19 The technique has been applied also for direct analysis of the carbon content in steel.…”

Investigation of optimized experimental parameters including laser wavelength for boron measurement in photovoltaic grade silicon using laser-induced breakdown spectroscopy

“…Laserna et al have demonstrated the capability of LIBS as a tool for the characterization of metal impurities (Ag, Ti, Al, and Cu), calcium, phosphorous and carbon for different silicon grades [10][11][12][13]. However boron impurities in silicon have up to now been measured only using Glow Discharge Mass Spectrometry (GDMS) and Inductively Coupled Plasma (ICP) [14][15][16].…”

2-D analysis of Ge implanted SiO2 surfaces by laser-induced breakdown spectroscopy

“…Sequential laser pulses on the same spot provide information on depth profiling of the materials. In the last decade, variety of applications concerning LIBS depth profiling with nanosecond and femtosecond lasers has been performed [10][11][12][13].…”