In this article, a simple numerical method to solve the general dynamic equation (GDE) has been described and the software made available. The model solution described is suitable for problems involving gas-to-particle conversion due to supersaturation, coagulation, and surface growth of particles via evaporation/condensation of monomers. The model is based on simplifying the sectional approach to discretizing the particle size distribution with a nodal form. The GDE developed here is an extension of the coagulation equation solution method developed by Kari Lehtinen, wherein particles exist only at nodes, as opposed to continuous bins in the sectional method. The results have been tested by comparison where simple analytical solutions are available, and are shown to be in excellent agreement. By example we apply the model to the formation and growth of Aluminum particles. The important features of the model are that it is simple to comprehend; the software, which we call nodal GDE solver (NGDE), is relatively compact; and the code is well documented internally, so that users may apply it to their specific needs or make modifications as required. The C files mentioned in this article are available online at http://taylorandfrancis.metapress.com/openurl.asp?genre= journal&issn=0278-6826. To access this file, click on the link for this issue, then select this article. In order to access the full article online, you must either have an institutional subscription or a member subscription accessed through www.aaar.org.

Single-crystal nanoparticles of silicon, several tens of nm in diameter, may be suitable as building blocks for single-nanoparticle electronic devices. Previous studies of nanoparticles produced in low-pressure plasmas have demonstrated the synthesis nanocrystals of 2-10 nm diameter but larger particles were amorphous or polycrystalline.This work reports the use of a constricted, filamentary capacitively coupled low-pressure plasma to produce single-crystal silicon nanoparticles with diameters between 20-80 nm.Particles are highly oriented with predominant cubic shape. The particle size distribution is rather monodisperse. Electron microscopy studies confirm that the nanoparticles are highly oriented diamond-cubic silicon.8ZH .RUWVKDJHQ HW DO

Single-crystal nanoparticles of silicon, several tens of nm in diameter, may be suitable as building blocks for single-nanoparticle electronic devices. Previous studies of nanoparticles produced in low-pressure plasmas have demonstrated the synthesis nanocrystals of 2–10 nm diameter but larger particles were amorphous or polycrystalline. This work reports the use of an inductively coupled low-pressure plasma to produce single-crystal silicon nanoparticles with diameters between 20 and 80 nm. Electron microscopy studies confirm that the nanoparticles are highly oriented diamond-cubic silicon.

Low pressure silane plasmas are known for their ability to synthesize silicon nanoparticles via gas phase nucleation. While in the past this particle formation has often been considered from the viewpoint of a contamination problem in semiconductor processing, we here describe a silane low pressure plasma that enables the synthesis of highly oriented, cubic-shaped silicon nanocrystals with a rather monodisperse size distribution. These silicon nanocubes have successfully been used in the manufacture of single nanoparticle vertical transistors. We discuss the advantages of this new paradigm of building nanoelectronic devices. The plasma synthesis process is characterized in more detail than in prior work. The particle nucleation, growth and shape evolution are studied. Results indicate that the process provides two spatially distinct zones: a diffuse plasma for particle growth and a constricted plasma zone for particle annealing. Measurements of the plasma ion density using a capacitive probe suggest that the plasma density in the constricted region of the plasma is about an order of magnitude higher than in the diffuse region, likely aiding the formation of cubic silicon nanocrystals. The process of particle extraction from the plasma reactor is discussed based on the balance of various forces acting on the particles. It is found that the use of a critical orifice for particle extraction enables the detrapping of particles which carry as many as 35 elementary charges.

No abstract