Semiconductors

Abstract

In the first chapters of this book we have used a model of the atom originally designed by Niels Bohr. It is easy to picture the Bohr atom, with its hard, bullet-like electrons hurtling round the massive nucleus just like planets orbiting a sun in a tiny solar system. The work done by Werner Heisenberg in the late 1920s showed that this model is unfortunately further from reality than we might find comfortable and that the atom is actually a rather fuzzy and uncertain thing, not at all like Bohr’s micro miniature solar system. This is not a book about atomic physics, so it is unnecessary to look too closely at the construction of atoms—but it is important to realise that there are ‘rules’ that appear to govern the behaviour of atoms and their component parts. Many of these rules seem contrary to what we would expect; but our intuition is necessarily based on our experience of the behaviour of objects much larger than atoms and electrons.