Semiconductor Physics
Modern electronics rests entirely on semiconductor physics. The behaviour of electrons in crystalline solids — described by quantum mechanics and statistical thermodynamics — gives rise to the p-n junction, the diode, and ultimately the transistor: the switching element that makes computers, radios, and virtually every electronic system possible. Part II builds the physical intuition from atomic bonds to working devices.
What You'll Learn in Part II
Understand how energy bands arise, what determines a bandgap, and how doping shifts the Fermi level.
Derive the Shockley equation from first principles, model rectifiers, and understand breakdown mechanisms.
Characterise BJT and MOSFET operating regions and build small-signal models for amplifier design.
Chapter 4: Band Theory & Semiconductors
Quantum origins of energy bands, intrinsic and doped semiconductors, carrier statistics, Fermi level, and drift/diffusion currents.
Chapter 5: PN Junctions & Diodes
Built-in potential, depletion region, Shockley diode equation, forward/reverse bias, breakdown, and rectifier circuits.
Chapter 6: Transistors: BJT & MOSFET
Bipolar and field-effect transistors: operating regions, current equations, small-signal models, and CMOS inverter operation.
Prerequisites
Part II builds on Part I (circuit fundamentals). A basic familiarity with quantum mechanics at the level of energy levels and wave functions is helpful but not strictly required — key results are stated and motivated physically before use. Statistical mechanics (Fermi-Dirac distribution) is introduced from scratch.