文档介绍：Encyclopedia of
Nanoscience and
Nanotechnology
Nanocluster Characterization
by EXAFS Spectroscopy
Giuseppe Faraci
Universitá di Catania;
Istituto Nazionale di Fisica della Materia, Catania, Italy
CONTENTS sophisticated growth techniques such as molecular beam epi-
taxy or chemical vapor deposition, capable of controlling at
1. Introduction the atomic level the interface between alternate films. Com-
2. EXAFS: General Considerations mon nomenclature is by now widely accepted for nanosized
3. EXAFS: Basic Principles structures: two-dimensional confined films are referred to as
4. EXAFS Data Analysis superlattices or quantum wells and one dimensional struc-
tures are named quantum wires, whereas zero-dimensional
5. Phase and Amplitude Transferability agglomerates are called quantum dots. For identifying an
6. Characterization of Nanoclusters ensemble of atoms or molecules, we will adopt the term
Glossary cluster since it does not contain any specific implication
about the shape, which therefore can be of spherical or
References island-like configuration. The description of any cluster-
related problem can also e plicated
1. INTRODUCTION whenever the initial state properties, due to the cluster
itself, are entangled with the so-called final state interac-
An aggregate of atoms or molecules monly referred tions, due to the presence of a substrate where the clus-
to as a cluster. The number of particles per cluster can be ter usually is deposited, or a matrix containing embedded
as small as two (dimer) up to several thousands. From the clusters. Of course, it would be greatly preferable to ana-
point of view of fundamental research, the physics of these lyze an in-flight cluster if the intrinsic cluster characteris-
agglomerates is of enormous interest. The possible realiza- tics should be investigated, avoiding therefore any influence
tion of size-controlled clusters gives the promising opportu- of spurious contributions or interactio