Glow discharge mass spectrometry (GDMS) utilizes ions generated in a dc inert gas plasma to sputter atoms into the ambient plasma from the surface of a. Glow Discharge Sputtering. • As the gas molecules are ionized and energized by collisions, eventually they will have enough energy to cause ejection of atoms. Emission spectroscopic studies of sputtering in a low-power glow discharge Glow discharge sputtering of chromium and niobium disk cathodes in argon.
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GLOW DISCHARGE SPUTTERING PDF
The new formulation removes most of the old difficulties and discrepancies. Glow discharge sputtering also shows definitely, however, that the phenomena are so complex that it will probably never be possible to develop a theory of sufficient accuracy to permit of exact conclusions being drawn from the experimental data.
Export citation and abstract. The anode glow discharge sputtering has a negative space charge and a moderate electric field. With longer glow discharge tubes, the longer space is occupied by a longer positive column, while the cathode layer remains the same.
Glow discharge - Wikipedia
An electric field increase results in the anode glow. Striations occur because only discrete amounts of energy can be absorbed or released by atoms, when electrons move from glow discharge sputtering quantum level to another.
The effect was explained by Franck and Hertz in Striations can be very annoying when they occur in fluorescent lamps. This process is called sputtering and it gradually glow discharge sputtering the cathode.
Sputtering is useful when using spectroscopy to analyze the composition of the glow discharge sputtering, as is done in Glow-discharge optical emission spectroscopy. For example, neon signs have hollow cathodes designed to minimize sputtering, and contain charcoal to continuously remove undesired ions and atoms.
Cathode Sputtering in Glow Discharges - IOPscience
Particles sputtered from the cathode are excited and emit radiation from the metals and oxides that make up the cathode. The radiation from these particles combines with radiation from excited carrier gas, giving the cathode region a white or blue color, while in the rest of the tube, radiation is only from the carrier gas and tends to be more monochromatic.
Surrounding the cathode is a negative field, which slows electrons as they are ejected from the surface. Only glow discharge sputtering electrons with the highest velocity are able to escape this field, and those without glow discharge sputtering kinetic energy are pulled back into the cathode.
Once outside the negative field, the attraction from the positive field begins to accelerate these electrons toward the anode. During this acceleration electrons are deflected and slowed down by positive ions speeding toward the cathode, which, in glow discharge sputtering, produces bright blue-white bremsstrahlung radiation in the negative glow region.
In this arrangement, the sample is used as the cathode. As mentioned earlier, gas ions and atoms striking the sample surface knock atoms off of it, a process known as sputtering.
The sputtered atoms, now in the gas phase, can be detected by atomic absorption, but glow discharge sputtering is a comparatively rare strategy. Instead, atomic emission and mass spectrometry are glow discharge sputtering used.
Collisions between the gas-phase sample atoms and the plasma gas pass energy to the sample atoms.
This energy can glow discharge sputtering the atoms, after which they can lose their energy through atomic emission. By observing the wavelength of the emitted light, the atom's identity can be determined.
By observing the intensity of the emission, the concentration of atoms of that type can be determined. Energy gained through collisions can also ionize the sample atoms. The ions can then be glow discharge sputtering by mass spectrometry.
In this glow discharge sputtering, it is the mass of the ions that identify the element and the number of ions that reflect the concentration. This method is referred to as glow discharge mass spectrometry GDMS and it has detection limits down to the sub-ppb range for most elements glow discharge sputtering are nearly matrix-independent.
Depth analysis[ edit ] Both bulk and depth analysis of solids may be performed with glow discharge. Bulk analysis assumes that the sample is fairly homogeneous and averages the emission or mass spectrometric signal over time.
- Glow-Discharge Sputtering
Depth analysis relies on tracking the signal in time, therefore, is the same as tracking the elemental composition in depth.