Insulating Semiconductor Nanowires For Ultrafast Electronics And Quantum Computers

Celso de Mello Donega (Debye Institute) will investigate a new hybrid method to make functional shells for semiconductor nanowires, using a combination of materials that has never been studied before. For this, Donega and Erik Bakkers (TU Eindhoven) have received an NWO TOP grant of 780,000 Euros. The researchers expect to deliver groundbreaking fundamental knowledge that will contribute to the development of ultrafast electronics, thermoelectric generators and quantum computers.

“You can use nanowires of certain materials to create special particles, called Majorana fermions, that are ideal for quantum computers,” Donega explains. “These particles have exceptional properties: no mass, no spin, no charge. Therefore, they can retain information for a long time, since they do not interact with the environment.” If you leave these wires bare, however, they lose information. Donega will therefore attempt to overcoat the nanowires with a layer of a different material: “Like the insulation around a copper wire.”

Special Properties
By choosing the composition and nanoscale dimensions of the wire and the coating carefully, the resulting core/shell nanowires gain special properties that are important for many applications, such as more efficient solar cells and LEDs, lasers, photo-detectors, photo catalysts and electronics. However, very specific conditions are required to make high quality shells. “The shell must have the same crystal structure as the nanowire core,” says Donega. “Otherwise, the shell is too brittle and defective, failing to protect the wire and easily falling apart.” In the project, Bakkers will make nanowires in his lab in Eindhoven, after which they will be very carefully transported to Utrecht. There, Donega will use a new microreactor to overcoat them with a shell.

Unique Combination
The unique combination of expertise of Donega and Bakkers is exceptionally well suited to make the research successful. Bakkers is a world expert in the making of nanowires via gas phase methods, and Donega is a world expert in the making of colloidal semiconductor nanocrystals in liquid phase, while retaining control over their composition, shape and size. In the project, Donega and Bakkers will be accompanied by two PhD candidates – one in Utrecht, one in Eindhoven – for the duration of the next four years.