Many of our electronic gadgets, such as computers, MP4 players, game consoles and mobile phones etc., are getting smaller, faster and equipped with larger memory capacity. The demand for speed and high information density in microchip has led to the continual shrinkage in the minimum feature size of semiconductor electronic devices. Over the past few decades, the number of transistors in the integrated circuit has increased exponentially and is doubling approximately every two years. This will inevitably lead to the miniaturisation of devices in to the nanometre scale regime. When approaching the nanoscale, quantum effects offer new possibilities for designing devices that will revolutionise areas from the electronics industry through to medicine.