With this new technique, the paper-thin computer is still too thick

While a paper-thin computer is still a dream for each of us, but with a new material, such computers are still too thick.

Engineers from Lawrence Berkeley National Laboratory of the US Department of Energy have developed a new way to produce transistors and circuits of only a few atoms thick. This technique depends on two important materials, conductive graphene and a semiconductor compound called Transmethal -metal di-chalcogenide or TMDC (a semiconductor atomic thickness between transition metals and Chalcogen such as sulfur, Selenium.

Since both of these materials are thin at the atomic level, this combination opens the door to the generation of 2D electronics. Moreover, this method is ready to apply in practice.

One layer TMDC monolithic structure, black atoms are transition metals like Mo, yellow atoms are chalcogen.

This may be good news for Moore's law, which predicts that transistor density will double every two years. It can be said that this law has led and inspired semiconductor research for nearly 50 years, but now it is entering its most fragile period. At 5nm to 10nm, computing techniques are resisting some of the basic laws of physics, especially those made from silicon.

Simply put, silicon is a material that accumulates . The semiconductor of Silicon occurs thanks to the addition of impurities to the grid structure in their crystals and the use of this arrangement requires the use of an accumulation of materials. Therefore, it seems that lowering the limit of silicon needed for semiconductor production will require new materials.

"When you reach this size, you won't be able to turn off silicon pads anymore," said Mervin Zhao, lead author of the new document released on Monday in Nature Nanotechonology. Berkeley lab, said . "At that time it would be like a broken switch."

Typical graphene material is a two-dimensional layer of carbon atoms.

Using graphene, an attractive metamaterial with desirable properties to become a two-dimensional crystal. While a single layer of graphene material lacks an electronic blank (bandgap: the distance between the valence band and the conduction band in the semiconductor), it therefore lacks the ability to "turn off the power" and cannot operate. efficient inside a transistor (actually a switch on and off electricity), it can be applied to deploy in wiring and network links in next generation devices.

As for the new semiconductor material here, the idea is to use graphene as a conductive substrate, through which channels can be etched with litho printing and then implanted with a TMDC called Molybden di- Sulfide (MoS2), so that it can grow itself (which is a popular method of building objects with nanoscale).

The carving process will leave small defects and spikes along the newly carved edges of the graphene, creating a place for TMDC to cling to and prioritize development along these edges. In this way, TMDC only grows inside these channels and does not grow on the relatively smooth surfaces above and below the graphene.

Raman Mapping: Raman spectroscopy chart and Photoluminescence mapping: fluorescence diagram.

While the two-dimensional graphene is not easy to "turn off" electricity, its conductive properties can be adjusted very carefully. It can tighten the electrical contact point between graphene and Molybden di-Sulfide in single Ohmic connections, or points where current flows from a semiconductor to a conductor and vice versa. This allowed the " heterostructure " needed to make active transistors, where graphene acts as an electrode to shoot electricity into Molybden di-Sulfide.

In the transistor figure below, the graphene regions will be placed on the underside of translucent white pieces, while the small squares of light blue squares are TMDC. The switching state of the transistor will be specified by the conductivity of the TMDC bridge, which is connected to graphene electrodes on the other side. This status will represent information.

The switching state of the transistor will be specified by the conductivity of the TMDC bridge.

As the notes of the document above, this basic idea was realized before, but it is only a proof of concept and not to the extent of expansion as it is now. While previous efforts have used relatively manual methods when building this architecture, researchers have developed their circuits chemically.

More precisely, they are self-assembling. This is possible because of the dual nature of graphene, both as a substrate for TMDC to develop, as well as an electrical contact point in the finished product.

To demonstrate the scalability of this technique, Berkeley researchers built a rectifier, or NOT gate, with a size of only millimeters."Now after demonstrating on a logical application, it is clear that controlling through arbitrarily designed models will provide the foundation for chemically developing atomic computing." They concluded.

In the future, these paper-thin devices may still be too thick.

While Zhao and his team seem to have solved a very profound problem, it is currently more basic knowledge than practical knowledge. While the transistors here may be as thin as one nanometer, we are still using millimeter-sized transistors both in length and width. Narrow current technology to the limits of silicon, where the length and width of transistors are comparable to the thickness of this material is still unspeakable.

"Will it work as a transistor when it reaches 5 nm, or I don't know . " Mr. Zhao said. "It may work, but there are still many issues that need to be resolved in how to assemble such materials together into electrical circuits. That's just the first step of this whole process."