EPFL researchers have developed a new high-precision technology that enables them to carve nanometric patterns into two-dimensional materials. The new technology allows the researchers to break the links between atoms with a miniature scalpel. The team says that it is extremely hard to structure to the materials using conventional lithography.
Conventional lithography uses aggressive chemicals or accelerated, electrically charged particles like electrons or ions. The problem is those methods can damage the properties of a material. The new technique uses a localized heat and pressure source to cut to the materials accurately. The team describes its technology as similar to the art of paper cutting, but a much smaller scale.
The tech uses heat to modify the substrate and make it more flexible. In some cases, it can even be turned into a gas. After that process, the 2D material can be more easily carved. In their research, the team used molybdenum ditelluride, a 2D material that is similar to graphene. The material is less than a nanometer thick.
Molybdenum ditelluride is placed on a polymer that reacts to temperature changes. When the polymer is exposed to heat, it sublimates, going from a solid to a gaseous state. Researchers heat a sharp, nano-sized tip to more than 180C and bring it into contact with the 2D material, and then apply a little force.
A computer-driven system controls the ultra-fast heating and cooling process and the position of the tip. The system allows researchers to make pre-defined indents to create the nanostrips that are used in nanoelectronic devices. Scientists say that their generic technology will be useful in the fields of nanoelectronics, nanophotonics, and nanobiotechnology to make electronic components smaller and more efficient.