Reviewed by Professor Robert Hamers, University of Wisconsin-Madison
The book ‘Silicon Nanocrystals’, edited by Lorenzo Pavesi and Rasit Turan, is an exceptionally well written compendium of articles describing the state-of-the art in silicon nanocrystals that should be of interest to anyone doing research in the nanoparticle field. The book has a number of exceptionally strong attributes. The first third of the book consists of a series of clear, well written chapters describing the electrical, optical, thermal, and chemical properties of silicon nanoparticles. These chapters are written from a pedagogical standpoint that extends well beyond silicon and should be of strong interest to anyone wanting to learn about the essential theoretical and experimental foundations of nanoparticles.
The book begins with an exceptionally clear and well written chapter by Bulutay and Ossicini on the electronic and optical properties of silicon nanocrystals from a theoretical/computational viewpoint, with basic principles illustrated through comparison of computational and experimental results. A particularly strong point of this chapter is its lucid explanation of computational methodologies, including a critical analysis of the weaknesses and strengths of different computational methods that should be accessible to anyone from graduate students to senior researchers. The authors lead the readers through a clear progression from H-terminated silicon and then systematically introduce the effects of changing the surface chemistry (e.g., oxidation), of doping, and of embedding the nanocrystals in a matrix, and extends beyond linear optics to discuss nonlinear optical properties. Overall, this is an excellent introduction to nanoparticles that should be of interest to anyone working on nanocrystals and gives the book a very strong start.
The next several chapters focus on specific properties in more detail. A chapter on how dopants affect the optical properties of Si NPs, by Fujii, nicely complements the earlier theoretical chapter. A chapter on electronic transport properties of ensembles of silicon nanocrystallites (by Balberg) begins with a clear development of percolation theory and summarizes how transport through systems is expected to vary depending on the nanoparticle density. It includes a scientifically critical analysis of the prior work on measurement of electrical properties of individual nanoparticles and ensembles of particles, followed by a systematic discussion of the electronic properties and how they vary as a function of density. A chapter on thermal properties includes a strong presentation of fundamental of thermal conductivity and of modern methods fo rmeasuring conductivity, including the “3w method”. The surface chemistry silicon nanoparticles is important in a number of different applications, and the book includes a good, albeit somewhat short, summary of some of the approaches taken to modify the surfaces of silicon nanoparticles. Chapter 7, on the role of Si nanocrystals in astrophysics, brings in a large body of literature from the astrophysics community that is not well known among chemists and physicists. In particular, it highlights a possible connection between silicon nanoparticles and the extended red emission that is observed in some cosmic environments. Additionally, it draws some connections between silicon nanoparticle growth in the cosmos and in the laboratory- for example, the growth of Si nanoparticles by disproportionation of SiO into Si + SiO2.
Later chapters focus on the synthesis and characterization of silicon nanoparticles and also include chapters on many of the potential applications of silicon nanocrystals in sensing, flash memory, photovoltaics, explosives, solid-state lighting, and optical communications. These individual chapters are necessarily more tightly focused on silicon, but taken as a whole the topics cover nearly every property of silicon nanoparticles.
What makes this book so refreshing is that most of the chapters are not simply reviews of the authors’ own work, but are instead written more from a strong pedagogical standpoint, with the salient points illuminated by specific comparisons and through many references to the scientific literature. This is particular true in the earlier parts of the book, as much of the pedagogy is not unique to Si but can be applied to almost any nanoparticle. In that respect, this book is one of the best publications I have seen describing the many unique properties of nanoparticles in general.
The earlier chapters of this book will be useful reading for anyone doing research in any type of nanomaterial, while the latter ones will be more valuable to those working in the Si nanoparticle field. Overall, it is hard to find any significant criticism of this book except possibly to note that there are some topics that it does not include. One omission some readers will notice is the absence of any substantial discussion of lower-dimensional structures such as 1-dimensional nanorods (nanowires) and 2-dimensional nanosheets. In addition, silicon nanoparticles and nanowires are of increasing importance as anodes for lithium-ion batteries, and coverage of this topic is absent. These are small omissions in an otherwise-excellent book and could perhaps serve as the nucleus for a second volume. This is a book that belongs on everyone’s bookshelf.