Glow discharge sample preparation

Sample state and preparation for glow-discharge sampling... 

This chapter deals exclusively with the methods that have been developed for the direct solids analysis of nonconductive samples by glow discharge mass spectrometry. The basic approaches to operation and sample preparation for the three primary methodologies of compaction, secondary cathode, and radio frequency powering are described. Examples of source performance and practical applications of each are taken from the analytical literature. Whereas this chapter de-... 

ICP emission spectroscopy is used primarily for the qualitative and quantitative analysis of samples that arc dissolved or suspended in aqueous or organic liquids. I he techniques for preparation of such solutions are similar lo tho.se described in. Section 9D-1 for flame absorption methods. With plasma emission, however, it is possible to analyze solid samples direclly. These procedures include incorporating electrothermal vaporization, la.ser and S[)ark ablation, and glow-discharge vaporization, all of which were described in Section 8C-2. Suspensions of solids in solutions can... 

Glow discharge (GD) Universal ionization, simple sample preparation Poor rejection of isobaric interferences... 

Generally, AES systems are calibrated with multi-element standard samples. In the case of sparks, arcs, glow discharges, and laser ablation, solid samples are required, which are rarely available in large enough numbers to provide a satisfactory calibration. Hence, in solid sample analysis secondary standards are usually prepared. 

Sample preparation facilities should include sectioning, grinding, polishing, etching (chemical plasma ion), vacuum glow discharge metallizing, critical... 

Fig. 5.36. The density of localized states g(E) plotted against - E for a number of a-Si specimens produced by glow discharge decomposition of silane. The samples were prepared on substrates held at different temperatures as noted in the figure. The point E Si indicates the lower limit for g(E) set by these experiments for an evaporated Si film. L and S denote linear and square low interpolations of g(E) to a value at E estimated from drift mobility (after Spear and LeComber (1972)).

Amorphous samples were prepared via the glow discharge of silane, and the kinetics of H exo-diffusion were studied by using conductivity, electron paramagnetic resonance, nuclear activation, and infra-red absorption methods. The results revealed the existence of two main stages of exo-diffusion. Below 500C, H evolution was controlled by a diffusion process which could be described by ... 

Samples were prepared by rf glow discharge decomposition of gas mixtures in a system designed to reduce contamination by water vapor or oxygen. 

---