New nano-antenna tech guides terahertz waves into ultra thin semiconductors, enabling lightning-fast switching speeds.
German researchers have developed a light-based technique to control the electronic behaviour of atomically thin semiconductors at unprecedented speeds, marking a potential leap forward for future nanoelectronic and optoelectronic devices.
A team from Bielefeld University and the Leibniz Institute for Solid State and Materials Research Dresden has successfully demonstrated how ultrashort terahertz light pulses can modulate materials like molybdenum disulphide (MoS₂) in real time. Their study, published in Nature Communications, showcases how electrical fields generated by light can alter the electronic structure of a semiconductor in less than a picosecond, one trillionth of a second.
At the heart of this breakthrough are specially engineered 3D–2D nanoantennas. These structures convert terahertz radiation, a band of electromagnetic waves between microwaves and infrared into vertical electric fields within the semiconductor. This interaction enables precise and ultrafast changes to the material’s properties using light alone, rather than relying on slower, conventional electronic switching.
The 3D–2D structure refers to a nanoscale antenna design where a three-dimensional metal shape directs terahertz light into an atomically thin, two-dimensional semiconductor layer. This setup concentrates the light’s energy vertically, creating strong electric fields within the 2D material. These fields allow ultrafast control of the semiconductor’s properties using light alone.
Traditionally, vertical electric fields in semiconductors are applied via electronic gates, which are limited in speed. This new approach bypasses that limitation, offering a light-driven control mechanism that could lead to a new class of ultrafast transistors and logic components.
The materials and antenna structures were developed and tested through extensive fabrication and modelling work. The result is a proof-of-concept system showing that atom-thin materials can be controlled with high-speed optical pulses in a coherent and selective manner.