Nicole Jessica Tibbetts

Capabilities and limitations of LA-ICP-MS for depth resolved analysis of CdTe photovoltaic devices

The analytical potential of ArF* excimer Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) is investigated for fast qualitative depth profile analysis of multi-layer CdTe photovoltaic (PV) devices. Critical parameters (e.g. laser fluence and laser repetition rate) are evaluated and optimized to reduce the aerosol mixing from consecutive laser shots and to achieve a low penetration rate. As a result, a high depth resolution (10 s of nm) is demonstrated through the analyses of superficial and embedded coatings. For instance, a layer with a thickness of 100 nm at a depth of 3 μm is successfully measured. Moreover, qualitative profiles of major and minor elements obtained by LA-ICP-MS are validated using reference techniques such as Secondary Ion Mass Spectrometry (SIMS) or Glow Discharge Time of Flight Mass Spectrometry (GD-TOFMS). Additionally, the shape and morphology of the laser-induced craters, after different numbers of laser shots, are investigated using mechanical profilometry and Atomic Force Microscopy (AFM), respectively.

Radiofrequency pulsed glow discharge-ToFMS depth profiling of a CdTe solar cell: A comparative study versus time of flight secondary ion mass spectrometry

In this manuscript, the authors compare and contrast depth profile data generated on the same commercially available CdTe cell using two analytical techniques, Time of flight secondary ion mass spectroscopy (ToF-SIMS), which is a well-established technique, and radiofrequency pulsed glow discharge (rf-PGD)-ToFMS, which is an emerging technique. The authors demonstrate that pulsed-rf-GD-ToFMS allows for a rapid analysis over a large (4 mm diameter) area of the sample at moderate vacuum conditions, while ToF-SIMS analyzes smaller regions (typically about 200 × 200 μm2) of the sample at ultrahigh vacuum conditions; the authors note that ToF-SIMS enables three dimensional analysis at micron or better lateral resolution. Both techniques show, in general, good agreement; however, some discrepancies are observed and discussed herein.