We have improved the methodology for producing nanowires. This means we can produce nanowires that contain two different semiconductors, namely gallium indium arsenide and indium arsenide. It is an enormous breakthrough, because for first time on a nanoscale, we can combine the desirable characteristics of these two materials thus gaining new possibilities for the electronics of the future, explains Peter Krogstrup.

Incredibly even today only 1 % of the world’s electricity comes from solar energy. This is because we are still experiencing difficulty in efficiently converting solar energy into electricity.  This latest breakthrough may change this statistic. Different materials capture energy from the sun in different and quite specific absorption areas. When we manufacture nanowires of gallium indium arsenide and indium arsenide, which each have their own absorption area, they can collectively capture energy from a much wider area, therefore utilizing more solar energy.

The nanowires of gallium indium arsenide and indium arsenide also have great potential in nanoelectronics. They can, for example, be used in the new OLED displays and LEDs. But it requires sharp transitions between the two materials in the nanowire.

The cultivation of nanowires takes place in a vacuum chamber. The researchers lay a gold droplet on a thin disc comprising of the semiconductor and the nanowire grows from below. In the transition between the two semiconductor materials in the gold droplet there was previously a mixing between the materials in the gold droplet and there was a soft transition between the materials. With the new method both of the materials can go from the top of the gold droplet or from the underside of the gold droplet. When the material comes from the underside, there is no mixing of the semiconductor materials. There is therefore a sharp transition on the atomic level between the gallium indium arsenide and indium arsenide.

This sharp transition between the two semiconductors is necessary for the current – in the form of electrons, to be able to travel with high efficiency between the two materials. If the transition is soft, the electrons can easily get caught in the border area. The new mixed nanowire can be beneficial for many areas of nano research around the world, comments Peter Krogstrup.