both text books (Kasap for ee2004, Sedra & Smith for ee2005) are very good,If you plan to major in microelectronics or circuit design, etc, Sedra & Smith can be good reference in future. This book is definitely much thicker than the notes. In fact, much of the lecture notes is taken from the textbook. Kasap is the best introductory text to semiconductors I ever know. Other books often involves too much math, but this book focuses on the physics, and is easier to understand.