Materials that consist of a layer just a few atomic layers thick promise promising applications for electronics and quantum technologies, for example. An international team led by TU Dresden has now made remarkable progress with an experiment at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The experts were able to induce an extremely fast switching process between electrically neutral and charged luminous particles in an ultra-thin two-dimensional material. The result opens up new perspectives for research, but could also create the basis for fast optical data processing and practical special detectors.
For the experiment, the experts chose the FELBE free-electron laser, which delivers very intense terahertz pulses. They first used it to illuminate a single-atom, strongly cooled layer of molybdenum diselenide. This light generated excitons. As soon as they were created, the exciton pairs each captured one of the electrons in the 2D material and thus became trions, which quickly decayed back into excitons by releasing an electron. The separation itself took place within a few picoseconds, almost a thousand times faster than was previously possible with purely electronic methods. The new method offers interesting prospects for research; unusual quantum states of matter, which arise from the interaction of many particles, would thus come within reach, as would applications at room temperature. There are also prospects for optical data processing and sensor technology.
