The utilization of sun light is one of the hottest topics in sustainable energy research. To efficiently convert sun power into a reliable energy – electricity – for consumption and storage, silicon and its derivatives have been widely studied and applied in solar cell systems. This handbook covers the photovoltaics of silicon materials and devices, providing a comprehensive summary of the state of the art of photovoltaic silicon sciences and technologies. This work is divided into various areas including but not limited to fundamental principles, design methodologies, wafering techniques/fabrications, characterizations, applications, current research trends and challenges. It offers the most updated and self-explanatory reference to all levels of students and acts as a quick reference to the experts from the fields of chemistry, material science, physics, chemical engineering, electrical engineering, solar energy, etc..

In terms of structure, the field of semiconductors spans a wide range, from the perfect order of single crystals to the non-periodic, disordered amorph ous state. The two extremes of this range attract a large amount of inter est. On one side, glamorous novel phenomena are being found which can only occur in specially tailored ultra-perfect periodic lattices. On the other side, the exotic and challenging nature of the amorphous state has triggered a surge of activity in recent years. Po1ycrystall i ne semi conductors are in between. They are among the work horses in the field, useful in many applications, a handy solution to many practical problems and still - they have not received in the past the amount of research interest that they deserve. It is the aim of the present book to improve this situation. The book originated from the lectures and seminars presented at the course on "Po1ycrystall i ne Semi conductors - Physical Properties and Applications" of "the International School on Materials Scien ce and Technology, hel d at the Centre for Sci entifi c Culture "Ettore Majorana" in Erice, Italy, July 1-15, 1984.

Covering topics that are especially important in electronic device development, this book surveys the properties, effects, roles and characterization of structurally extended defects in semiconductors. The basic properties of extended defects are outlined, and their effect on the electronic properties of semiconductors, their role in semiconductor devices, and techniques for their characterization are discussed. This text is suitable for advanced undergraduate and graduate students in materials science and engineering, and for those studying semiconductor physics.

It is nonnal for the preface to explain the motivation behind the writing of the book. Since many good books dealing with the general theory of crystal defects already exist, a new book has to be especially justified, and here its main justification lies in its treatment of crystal line interfaces. About 1961, the work of the author, essentially based on the fundamental work of Professor F. C. Frank, started to branch away from the main flow of thought in this field and eventually led to a general geometrical theory which is presented as a whole for the first time in this book. Although nearly all that is presented has already been published in different journals and symposia, it might be difficult for the reader to follow that literature, as a new terminology and new methods of analysis had to be developed. Special emphasis is given to discussion and many diagrams are included in order that a clear view of the basic concepts be obtained. Intennediate summaries try to bring out the main points of the chapters. Instead of specific exercises, general suggestions for them are given. The part up to chapter 9 is considered more or less as introductory, so that the book can be studied without specific knowledge of crystals and crystal defects. The presentation of that part developed out of lectures given by the author at the Swiss Federal Institute of Technology (ETH) in Zurich.

From its early beginning before the war, the field of semiconductors has developped as a classical example where the standard approximations of 'band theory' can be safely used to study its interesting electronic properties. Thus in these covalent crystals, the electronic structure is only weakly coupled with the atomic vibrations; one-electron Bloch functions can be used and their energy bands can be accurately computed in the neighborhood of the energy gap between the valence and conduction bands; nand p doping can be obtained by introducing substitutional impurities which only introduce shallow donors and acceptors and can be studied by an effective-mass weak-scattering description. Yet, even at the beginning, it was known from luminescence studies that these simple concepts failed to describe the various 'deep levels' introduced near the middle of the energy gap by strong localized imperfections. These imperfections not only include some interstitial and many substitutional atoms, but also 'broken bonds' associated with surfaces and interfaces, dis location cores and 'vacancies', i.e., vacant iattice sites in the crystal. In all these cases, the electronic structure can be strongly correlated with the details of the atomic structure and the atomic motion. Because these 'deep levels' are strongly localised, electron-electron correlations can also playa significant role, and any weak perturbation treatment from the perfect crystal structure obviously fails. Thus, approximate 'strong coupling' techniques must often be used, in line' with a more chemical de scription of bonding.