Depth Profile Analysis of Molybdenum Disulfide Film by Glow Discharge Mass Spectrometry

Abstract

In this work, the depth profile analysis capability with direct current glow discharge mass spectrometry (dc-GD-MS) was evaluated by examining molybdenum disulfide (MoS2) films on Al and steel substrates. The optimized glow discharge conditions for obtaining an ideal flat crater and an efficient signal intensity were a discharge current of 1.0-1.5 mA and a discharge pressure of 4.7 mPa. The dc-GD-MS depth profile analysis provided depth resolutions of 0.55 μm for the MoS2/Al sample and 0.70 μm for the MoS2/Steel sample. The interface of 4.46 μm for MoS2/Al and 4.55 μm for MoS2/Steel determined by dc-GD-MS was close to the thicknesses of 4.85 μm and 5.45 μm, respectively, as measured by field emission scanning electron microscopy (FE-SEM). A high-carbon steel standard sample (NIST SRM 1264a) was used to validate the reliability and accuracy of the method. Relative errors of less than 12% were obtained compared with the certified concentration and the relative standard deviation (RSD, n = 20) of typical elements within 10%. The dc-GD-MS depth profile analysis provided an efficient and reliable approach for the depth analysis of the MoS2 film.

Depth Profiling At A Steel-Aluminum Interface Using Slow-Flow Direct Current Glow Discharge Mass Spectrometry

“…Wang et al demonstrated that a sample with a film thickness in the range of 4-5 µm resulted in a depth resolution in the range of 0.5-0.7 µm. 35 A slow-flow instrument (AutoConcept GD 90) was used in that study, which is similar to the Astrum GDMS in terms of operating parameters and sputtering rates. 35 Therefore, poor depth resolution is potentially linked to the thickness of the steel layer for the samples used in the present study, which is approximately 80 and 30 µm for the treated and untreated samples, respectively (Figs.…”

Studies of Dopamine Oxidation Process by Atmospheric Pressure Glow Discharge Mass Spectrometry

“…Hence, it is critical to apply sensitive and accurate methods to characterise and understand the oxidative pathways and metabolites of DA. Many methods, including NMR [4], EPR [5], mass spectrometric [6,7] and spectroscopic techniques [8,9], have been applied to study the DA oxidation pathway. However, DA is highly active and easily undergoes autoxidation, metal oxidation, or enzymatic oxidation in the cytoplasm [10][11][12].…”