DC glow discharge

Figure C2.13.3. Schematic illustrations of various electric discharges (a) DC-glow discharge, R denotes a resistor (b) capacitively coupled RF discharge, MN denotes a matching network (c), (d) inductively coupled RF discharge, MN denotes matching network (e) dielectric barrier discharge.

Figure 1 Schematic of DC glow-discharge atomization and ionization processes. The sample is the cathode for a DC discharge in 1 Torr Ar. Ions accelerated across the cathode dark space onto the sample sputter surface atoms into the plasma (a). Atoms are ionized in collisions with metastable plasma atoms and with energetic plasma electrons. Atoms sputtered from the sample (cathode) diffuse through the plasma (b). Atoms ionized in the region of the cell exit aperture and passing through are taken into the mass spectrometer for analysis. The largest fraction condenses on the discharge cell (anode) wall.

Fig. 2. Distribution of voltage, field, space charge, and current density in a dc glow discharge...

Q. What property must the sample possess in order to be amenable to analysis by DC glow discharge spectrometry ... 

A GD mass spectrometer from Thermo Fisher Scientific with a direct current (dc) glow discharge ion source based on the mass spectrometric arrangement of the Element (Element GD) has been available on the analytical market since 2005 for sensitive multi-element analysis of trace impurities in conducting samples. The experimental arrangement of the dc GD ion source (Grimm type) and... 

Figure 5.27 Schematic diagram of direct current (dc) glow discharge mass spectrometer (VC 9000).

Plasma CVD has been used since the middle of the 1970s. For the creation of the plasma, DC glow discharge [224], RF glow discharge [219, 225-227], microwave plasma [228, 229], or plasma jets [230] are used. 

The microwave-induced plasma (MIP) is the most popular plasma used for conventional GC-OES. However, the DC glow discharge plasma has recently received more attention because it can be operated at a low temperature, albeit at a low pressure 1-30 Torr so as to avoid excessive gas heating and arcing. 

This plasma detection method was also applied to detect a copper(II) ion solution (0.1 M) in a glass chip. Here, the liquid sample itself was employed as the cathode for the DC glow discharge, using Ar as the carrier gas [719]. 

Eijkel, J.C.T., Stoeri, H., Manz, A.J., An atmospheric pressure dc glow discharge on a microchip and its application as a molecular emission detector J. Anal. Atom. Spectrom. 2000, 15, 297-300. 

The simplest approach for the deposition of ZnO films by sputtering is sketched in Fig. 5.1 A DC glow discharge is ignited between a cathode, which is a planar Zn target, and the anode, which is the chamber of the vacuum system. The system is pumped to a pressure of T0Pa and Ar and O2 are introduced into the system. 

Detailed descriptions of the rf and dc glow-discharge deposition techniques are presented by Hirose and Uchida in Volume 21 A, Chapters 2 and 3. 

In Volume 21, Part A, the preparation of a-Si H by rf and dc glow discharges, sputtering, ion-cluster beam, CVD, and homo-CVD techniques is discussed along with the characteristics of the silane plasma and the resultant atomic and electronic structure and characteristics. 

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