Chip Manufacturing Innovations: Controlling Exciton Flow in Semiconductors

Researchers at Carnegie Mellon University, UC Riverside, and other institutes have introduced a new method to control exciton flow in semiconductor structures known as moire superlattices. This innovative approach focuses on interlayer exciton diffusion in a WS2/WSe2 moire superlattice, utilizing correlated electrons to enhance exciton transport.

In their study published in Nature Communications, the team found that by actively tuning electronic states through electrostatic doping, they could significantly influence exciton diffusivity. Senior author Sufei Shi stated that when electrons in the moire superlattice reached a density sufficient to form a Mott insulator state, exciton flow was enhanced by up to 100 times.

Conversely, exciton diffusivity was suppressed when electron arrangements formed a Wigner crystal state. This breakthrough presents new avenues for developing quantum devices and optoelectronics by allowing for the electrical tuning of exciton dynamics, which could lead to the creation of devices that utilize excitons as information carriers rather than electrons.

Shi emphasized the potential to utilize the interaction between correlated electrons and excitons to achieve more robust control over exciton transport, paving the way for advanced semiconductor technologies.

The research opens the door for future studies aimed at manipulating exciton diffusivity via electric fields or nanoscale device patterns, as well as exploring exciton-exciton interactions.