For example, while one layer of this new kind of superlattice can allow a fast flow of electrons through it, the other type of layer can act as an insulator. This design confines the electronic and optical properties to single active layers, and they do not interfere with other insulating layers.

Such superlattices can form the basis for improved and new classes of electronic and optoelectronic devices. Applications include superfast and ultra-efficient semiconductors for transistors in computers and smart devices, and advanced LEDs and lasers.

Compared with the conventional layer-by-layer assembly or growth approach currently used to create 2D superlattices, the new UCLA-led process to manufacture superlattices from 2D materials is much faster and more efficient. Most importantly, the new method easily yields superlattices with tens, hundreds or even thousands of alternating layers, which is not yet possible with other approaches.

This new class of superlattices alternates 2D atomic crystal sheets that are interspaced with molecules of varying shapes and sizes. In effect, this molecular layer becomes the second “sheet” because it is held in place by “van der Waals” forces, weak electrostatic forces to keep otherwise neutral molecules “attached” to each other. These new superlattices are called “monolayer atomic crystal molecular superlattices.”

The study, published in Nature, was led by Xiangfeng Duan, UCLA professor of chemistry and biochemistry, and Yu Huang, UCLA professor of materials science and engineering at the UCLA Samueli School of Engineering.

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