Glow discharge optical emission spectrometry elemental mapping with restrictive anode array masks

Abstract

Large-area surface elemental mapping is highly beneficial for a multitude of applications in fields from materials science to biology. Current typical methods, however, suffer from long acquisition times. Glow Discharge Optical Emission Spectrometry (GDOES), under pulsed-power and higher pressure operation, exhibits a great potential for ultrahigh throughput chemical imaging of large surface area samples. Up until now, various proof-of-principle studies of GDOES elemental mapping have only been applied to smaller surface area samples. Thus, there is a need for development of GDOES systems that allow for analysis of large area samples. Here, the design of different GD configurations for large area sample (10 cm diameter) analysis is investigated as a function of operating conditions such as pressure (133-4000 Pa), applied power (up to 5 kW), and pulsing. An open face electrode (OFE) design generatedundesirable heterogeneous plasma at the higher pressures required for achieving spatial resolution. On the other hand, a restrictive anode array mask (RAAM) design provided notable homogeneity within the same pressure range and enabled the lateral resolution of 1 mm diameter silver inclusions embedded in copper. RAAMS were designed varying thickness (3 mm and 12 mm), aperture size (4, 6, 8 mm), geometry, and grounding. Also, as the section sputtered is restricted to the area covered by the apertures, the RAAM provides the opportunity for subsequent analysis of the unsputtered regions via alternative methods. In addition, the RAAM permits higher power densities to be achieved within the limitations of the power supply. These findings help to pave the way for exploiting the full potential of GDOES and its ultrahigh throughput elemental mapping of large surface area samples.

The 2017 Plasma Roadmap: Low temperature plasma science and technology

“…Coupling with a spatially selective, time-gated optical detector, e.g. an intensified CCD allows one to obtain lateral resolution of sample surface composition [148].…”

Compressed sensing spectral imaging for plasma optical emission spectroscopy

“…The mirrors of the DMD are aligned in a diamond grid such that the lines in one dimension are straight and in the other they are zigzag which results in the interline distance being twice in one dimension vs. the other. Thus, the height of each resultant image had to be adjusted by a factor of 1 2 . The multiplexed light was then collected through another series of collimating and focusing lenses and was focused onto the entrance slit of a monochromator (Bentham M300, 1200 g mm À1 ).…”

“…Such information is important to improve the understanding of samples of interest as well as optimize the performance of relevant systems. In the case of plasma optical emission spectroscopy (OES), spectral imaging plays a critical role in application development, for example in the case of glow discharge surface elemental mapping 1,2 or inductively coupled plasma matrix-effect agging. 3,4 In addition, spectral imaging has become essential in plasma fundamental studies for glow discharge, 5,6 inductively coupled plasma, [7][8][9] dielectric barrier discharges, 10,11 laser induced breakdown plasmas, 12,13 etc., to better understand the underlying plasma mechanisms.…”

High-throughput single pixel spectral imaging system for glow discharge optical emission spectrometry elemental mapping enabled by compressed sensing

“…Glow discharge optical emission spectroscopy (GDOES) has been shown to permit EM from within the sputtered area when operated in pulsed power mode and sustained under higher-than-typical pressures. [8][9][10][11][12][13][14][15] Leveraging the inherent GDOES advantages of direct solid sampling, simultaneous multi-elemental analysis, fast sputtering rates, multi-matrix calibration schemes, and depth proling in the nm scale, results in ultra-high throughput elemental mapping capabilities that can be several orders-ofmagnitude faster vs. typical techniques. 2,11,16 One of the aspects that enables GDOES EM is its coupling to an appropriate spectral imaging system for data collection, with several embodiments reported.…”