For decades two things have been at the heart of electronics; transistors and semiconductors. The use of semiconductors though may hit a wall in the next decade or two as their physical limitations will prevent further miniaturization. Researchers at Michigan Technological University however have found a way to build a transistor without a semiconductor, and not only can it reach smaller sizes, but it also operates without leakage.
What has made semiconductors so important to electronics is that they can be switched from an insulating to a conducting state, and back, by an electrical signal. The researchers managed to replicate this behavior though using quantum tunneling, which also behaves differently depending on the signal applied. Starting with boron nitride nanotubes, an insulating material, the researchers used lasers to apply quantum dots of gold to them, creating quantum dot-boron nitride nanotubes (QD-BNNTs). After being hooked up to electrodes, it was discovered that electrons would tunnel from one quantum dot to another.
Researchers have previously built nanotube devices that behave similarly, but had the unfortunate requirement of being chilled by liquid helium. This new device operates at room temperature, and because of the precision of the tunneling, does not suffer from leakage, so it will stay cool while operating.