A joint research team from the Institute for Basic Science (IBS), UNIST, and POSTECH has enhanced the room-temperature luminescence performance of a 2D semiconductor-based quantum light source. This is the result of controlling the exciton diffusion problem, which has been cited as a hurdle for room-temperature operation, through nano-structure design.

The results of this study were published in the international journal Science Advances on March 13. The research team noted that while two-dimensional semiconductors have been attracting attention as next-generation optoelectronic materials, at room temperature, excitons spread easily and excess charge interferes with light emission, making it difficult to stably emit light at specific locations.

Excitons are quasiparticles formed by the combination of electrons and holes, playing a key role in generating light in semiconductors. In particular, localized excitons, which remain in a narrow region, have great potential as quantum light sources, but their formation has been difficult in room-temperature environments with high thermal energy. To overcome this limitation, the research team placed a nanohole structure with a diameter of 500 nanometers beneath a two-dimensional semiconductor and cleared the charge environment by removing the water layer between the semiconductor and the gold substrate through heat treatment.

In this process, excitons gathered in a narrow region at the center of the nanohole, and the conditions for them to be emitted as light without losing energy were also improved. According to the research team, the exciton confinement efficiency was found to be approximately 98%, and the luminescence efficiency increased by about 130 times compared to existing methods. The team explained that through this, they confirmed that a two-dimensional semiconductor-based light source can operate relatively brightly and stably even at room temperature.

This achievement is significant in that it expands the scope of research on quantum photonic devices operating at room temperature. However, rather than immediately entering the commercialization stage, this research is closer to presenting a structure capable of precisely controlling the processes of light generation and extinction at room temperature. The research team anticipates that by further fine-tuning the nanostructure and refining light irradiation conditions, this research could be extended to room-temperature single-photon sources in the future.