Preface known as photovoltaic devices, in several application sections. This also reflects my long study of that field TOPICS AND USE OF THE BOOK I have taught a class based on the material that is presented in this book for many years. I get through most of the topics, excluding detailed discussions of the applications, in one semester. Each chapter typically gets about three hours of lecture, although Chapters 6, 7, 9, and 12 often receive four to five lectures and Chapter I gets one hour. My students have generally been a mixture of senior undergraduate and graduate students. One of the common features of these students is that many, especially the graduate students, lack a strong background in some one of the underlying prerequisite subjects such as condensed matter physics, principles of electronic devices. or materials science. Therefore the book includes a brief review of these topics in Chapters 2-4 and I cover these subjects very quickly in the class. Even for the students with a background in all of these areas I usually find it helpful to review selected topics from these chapters. In presenting review topics I ope that the book can be useful to a student body that completely lacks a detailed background if the instructor is willing to go through this material One of the challenges in writing the book is that its intended audience does not have nuch background in quantum mechanics. Therefore, I cannot practically go into details about how the wave function interactions in Chapter 5 are calculated that lead to the matrix element values in the lCAo matrix(or into details of corrections to the lCao that are used in real calculations today. I have attempted to present the material in such a way that a student without this background can understand the important take-home messages of the subject even if they are unfamiliar with how the values are derived Of course, if one is doing tight binding theory these matrix elements may be considered fitting parameters, so what I am doing in Chapter 5 is not so much less sophisticated than tight binding theory anyway. One may also note that I have taken two approaches to the question of how atomic orbitals contribute to miconductor band structures in Chapter 5, one almost purely visual the Harrison diagram approach-and one semiquantitative, covering the basic approach of lCAo theory. Hence, hopefully the student will have different ways of remembering the lationships among orbitals, bonds, and bands. It is useful when covering the Aterial to also make connections to the material in Chapter 2 on nearly free electron Chapters 6 and 7 are the core of the materials science in the book. They talk about how to engineer a semiconductor material to achieve given properties through modification of its structure and chemistry. Hence, they spend a considerable time on defects and how and why they form. Most of the preceding chapters are building up to these two in hopes that when the student gets here they will say to themselves"of course it should work this way, considering how the atoms are changing and how formingviii known as photovoltaic devices, in several application sections. This also reflects my long study of that field. TOPICS AND USE OF THE BOOK I have taught a class based on the material that is presented in this book for many years. I get through most of the topics, excluding detailed discussions of the applications, in one semester. Each chapter typically gets about three hours of lecture, although Chapters 6, 7, 9, and 12 often receive four to five lectures and Chapter 1 gets one hour. My students have generally been a mixture of senior undergraduate and graduate students. One of the common features of these students is that many, especially the graduate students, lack a strong background in some one of the underlying prerequisite subjects such as condensed matter physics, principles of electronic devices, or materials science. Therefore the book includes a brief review of these topics in Chapters 2-4 and I cover these subjects very quickly in the class. Even for the students with a background in all of these areas I usually find it helpful to review selected topics from these chapters. In presenting review topics I hope that the book can be useful to a student body that completely lacks a detailed background if the instructor is willing to go through this material. One of the challenges in writing the book is that its intended audience does not have much background in quantum mechanics. Therefore, I cannot practically go into details about how the wave function interactions in Chapter 5 are calculated that lead to the matrix element values in the LCAO matrix (or into details of corrections to the LCAO that are used in real calculations today. I have attempted to present the material in such a way that a student without this background can understand the important take-home messages of the subject even if they are unfamiliar with how the values are derived. Of course, if one is doing tight binding theory these matrix elements may be considered fitting parameters, so what I am doing in Chapter 5 is not so much less sophisticated than tight binding theory anyway. One may also note that I have taken two approaches to the question of how atomic orbitals contribute to semiconductor band structures in Chapter 5, one almost purely visual – the Harrison diagram approach – and one semiquantitative, covering the basic approach of LCAO theory. Hence, hopefully the student will have different ways of remembering the relationships among orbitals, bonds, and bands. It is useful when covering the material to also make connections to the material in Chapter 2 on nearly free electron behaviors. Chapters 6 and 7 are the core of the materials science in the book. They talk about how to engineer a semiconductor material to achieve given properties through modification of its structure and chemistry. Hence, they spend a considerable time on defects and how and why they form. Most of the preceding chapters are building up to these two in hopes that when the student gets here they will say to themselves “of course it should work this way, considering how the atoms are changing and how the bonds are forming.” Preface