Semiconductors can trash economies and may well start next World War - but what are they?

Semiconductors are the bedrock of modern electronics. They replaced old-school transistors and there are billions of them in the phone in your pocket. Semiconductors are at the heart of everything from TVs, to cars to washing machines, to missiles. Little wonder then that their shortage can dramatically impact the world's economies or that China is eyeing the semiconductor expertise of its neighbour Taiwan. Here Associate Professor Ke Li of Nottingham University explains what they are and why they matter.