"This one-stop study aid to TFETs is aimed at those who are beginning their study on TFETs and also as a guide for those who wish to design circuits using TFETs. The book covers the physics behind the functioning of the TFETs and their modelling for the purpose of circuit design and circuit simulation. It begins with a brief discussion on the basic principles of quantum mechanics and then builds up to the physicsbehind the quantum mechanical phenomena of band-to-band tunnelling. This is followed by studying the basic functioning of the TFETs and their different structural configurations. After explaining the functioning of the TFETs, the book describes different approaches used by researchers for developing the drain current models for TFETs. Finally, to help the new researchers in the area of TFETs, the book describes the process of carrying out numerical simulations of TFETs using TCAD. Numerical simulations are helpful tools for studying the behaviour of any semiconductor device without getting into the complex process of fabrication and characterization"--Abstract: Research into Tunneling Field Effect Transistors (TFETs) has developed significantly in recent times, indicating their significance in low power integrated circuits.