Kavli Institute for Nanoscience, Delft University of Technology, The Netherlands
In this lecture we will review the working principles of transistors and their evolution from the first bipolar device in 1947 to state-of-the-art field-effect nanodevices that will power future computers. This evolution was not only based on the invention of the transistor concept. The key development was actually material control--Germanium in the beginning, then Silicon, now compound semiconductors--which remains a core issue for today’s nanodevices. We will focus both on the quest for smaller, faster and more energy efficient industrial devices as on the ultimate limit of transistors where a single molecule or atom determines the current flow in the device. The functionality of the latter is not based on the evolutionary scaling of the original transistor concept, but rather on the quantum nature of the device. Besides the bulk physics of the bipolar and field-effect transistor, the atomistic approach needed to understand the ultimate limit of transistors such as resonant tunneling, charging and orbital effects will be discussed.