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Studies the radiative efficiency of the 147 nanometer resonance radiation of xenon excited in a low pressure, high frequency surface wave sustained in plasma. Optical absorption spectroscopic measurements; Monte Carlo calculations of the effective decay rate; Efficiencies.

Examines the radial distribution of electron and ion fluxes to conducting and nonconducting walls in a planar inductively coupled plasma. Significance of the ion impact energies measured on a conducting surface; Advantages of discharge systems which are capable of producing low-pressure high-density plasmas; Information on spatial plasma uniformity; Influence of the radial variation of the sheath voltage drop on the radial behavior of ion energy distribution.

Presents a study which analyzed the spatial dependence of the electron distribution function (EDF) and of related macroscopic parameters in an inductively coupled argon plasma at 13.56 megahertz. Generation of the radio frequency induction field; Function of the total energy of electrons; Way in which the axial variation of the EDF is described.

While the formation of nanoparticles in nonthermal plasmas is well known, the heating mechanism leading to their crystallization is poorly understood. In this study, we investigate the crystallization of amorphous silicon nanoparticles in nonthermal plasmas using a tandem plasma configuration. Amorphous silicon nanoparticles with diameters of 3, 4 or 5 nm are formed in a low-power nonthermal upstream plasma, and injected directly into a second separate downstream plasma. Crystallization of the amorphous silicon nanoparticles is investigated as a function of the power used to maintain the second plasma. This approach allows for the decoupling of nanoparticle synthesis and heating. The nanoparticle properties and plasma conditions are examined to obtain a comprehensive understanding of nanoparticle heating and crystallization. The particle crystallinity was studied using x-ray diffraction, Raman spectroscopy, and transmission electron microscopy. We discovered a threshold power for complete crystallization of the particles. A combination of comprehensive plasma characterization with a nanoparticle heating model reveals the underlying plasma physics leading to crystallization. Here we found that the nanoparticles reach temperatures as high as 750–850 K in the secondary plasma, which is well above the gas temperature and sufficient for complete nanoparticle crystallization. While we demonstrate this method of predicting nanoparticle temperature using silicon, the approach can be applied broadly to other plasma-synthesized nanomaterials. [ABSTRACT FROM AUTHOR]

The electron kinetics of low-pressure plasmas is often dominated by the so-called “nonlocal” behavior of electrons which becomes evident if the electron energy relaxation length is of the order or larger than typical discharge dimensions. In this paper, a brief review of the various manifestations of “nonlocal electron kinetics” is given. Two effects based on nonlocal electron behavior are discussed in more detail. (1) In a steady-state inductive plasma, a flux pattern in electron energy–configuration space was observed through Langmuir probe measurements which resembles a convection cell. Comparisons between Langmuir probe measurements and numerical solutions of the Boltzmann equation are presented. (2) The temporal evolution of the electron distribution function was studied in the afterglow of a pulsed inductive plasma. An unusually fast decay of the electron mean kinetic energy was observed which is related to “diffusive cooling” of electrons. [Copyright &y& Elsevier]

The resonance cone (rc) diagnostic is usually based on kinetic theory within the electrostatic approximation. Numerical and experimental results are presented, which reveal the influence of the neglected electromagnetic terms in the dispersion relation. In the near field a shift of the rc toward smaller angles occurs, which may be important at high electron densities and temperatures. In the far field the phase variation inside the cone turns out to be useful as a new electron density diagnostic in the regime of high densities, where the rc diagnostic was previously not applicable. [ABSTRACT FROM AUTHOR]

Examines the potential of dust acoustic waves for using an accurate particle size diagnostic of nanometer-sized contaminant particles on plasma. Analysis on dispersion characteristics of dust acoustic waves in the plasma; Description of dust component as a single fluid; Use of acoustic waves as a novel particle size diagnostic.

The composition, structure, light emission and oxidation kinetics of Si1[?]xGex alloy nanocrystals ([?]3 nm in diameter) synthesized by nonthermal plasma have been investigated. It is found that the synthesized nanocrystals are neither a mixture of Si nanocrystals and Ge nanocrystals nor Si-Ge (Ge-Si) core-shell nanocrystals. The H coverage at the surface of Si1[?]xGex nanocrystals decreases with the increase of the Ge atomic fraction. The incorporation of Ge enhances the oxidation of Si1[?]xGex nanocrystals when the atomic fraction of Ge is <0.5. No shift in photoluminescence from hydrosilylated Si1[?]xGex nanocrystals is observed when the atomic fraction of Ge varies between 0 and 0.1, indicating that the bandgap of Si nanocrystals is similar to that of Ge nanocrystals at a nanocrystal size of 3 nm. [ABSTRACT FROM AUTHOR]

The future exploitation of the exceptional properties of freestanding silicon nanocrystals (Si NCs) in marketable applications relies upon our ability to produce large amounts of defect-free Si NCs by means of a low-cost method. Here, we demonstrate that Si NCs fabricated by scalable rf plasma-assisted decomposition of silane with additional hydrogen gas injected into the afterglow region of the plasma exhibit immediately after synthesis the lowest reported defect density, corresponding to a value of only about 0.002-0.005 defects per NC for Si NCs of 4 nm size. In addition, the virtually perfect hydrogen termination of these Si NCs yields an enhanced resistance against natural oxidation in comparison to Si NCs with nearly one order of magnitude larger initial defect density. [ABSTRACT FROM AUTHOR]