Combination of nanotubes and silicon makes nano-LEDs possible

Researchers have developed a method to integrate nanowires into electronic circuits. The solution provides high yields of circuits that can be manufactured at low cost.

Collaborators from Harvard University’s School of Engineering and Applied Sciences and a collaborator from Jena University detailed their method of integrating carbon nanowires with silicon circuits in the Nano Letters issue. published. Thanks to their patented technology, mass production of combinations of CNTs and traditional chips is possible and economically feasible. Not only electronic circuits can be built with the new combinations, optical chips are also possible.

In their method, the researchers use standard photolithographic processes and a technique that is common in silicon chip production: glass as an insulator that is deposited on the wafer. The nanowires are placed between a silicon substrate and a conductive top layer. To prevent contact between the p-doped silicon and the metal contact on the top, an insulating layer of glass is applied. By applying a voltage between the substrate and the top contact, the carbon wires receive current. For example, the team succeeded in constructing LEDs in which the wavelength of the photons depends on the type of CNT used.

As a demonstration, the researchers showed a wafer with hundreds of LEDs built from nanotubes containing zinc oxide. For now, the team has no control over the orientation of the tubes on the silicon, but the researchers are working on a way to control the direction in which the cnts lie. The method could pave the way for chips with a large number of nano-lasers that could serve as optical interconnects, for example.