Ultrafast Exciton–Polariton Dynamics and Plasmonic Photogating Enhancement in Scalable 2D TMDC Platforms

YU-JUNG LU^1,2*

¹Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
²Department of Physics, National Taiwan University, Taipei, Taiwan

* Presenter:YU-JUNG LU, email:yujunglu@gate.sinica.edu.tw

Absorption of photons in atomically thin materials has become a challenge in the realization of ultrathin high-performance optoelectronics. While numerous schemes have been used to enhance absorption in two-dimensional (2D) semiconductors [1], such enhanced device performance in scalable monolayer [2] photodetectors remains unattained. Here, we demonstrate wafer-scale integration of monolayer single-crystal MoS₂ photodetectors with a nitride-based plasmonic metasurface to achieve a high detectivity of 2.58 × 1012 Jones with a record-low dark current of 8 pA and long-term stability over 40 days [3]. We observed an enhancement factor greater than 100 compared to control devices, which can be attributed to the local strong electromagnetic (EM) field’s enhanced photogating effect by the resonant plasmonic metasurface. The combination of monolayer 2D materials with nitride-based plasmonic metasurfaces opens new possibilities for boosting the performance of optoelectronic devices with design flexibility that accommodates various 2D materials. To further extend the functional scope of 2D platforms, polariton-mediated ultrafast nonlinear energy transfer in WS₂/Al₂O₃ superlattices demonstrates how strong light–matter coupling can enable sub-picosecond active modulation under strong coupling conditions [4]. Given that 2D semiconductors and hafnium nitride (HfN) are not only Si CMOS process compatible but also achievable over wafer scales, our results pave the way for seamlessly integrating 2D semiconductor-based photodetectors into imaging, sensing, and optical communications applications. We discovered several unique working mechanisms that use nitride-based plasmonic nanostructures to improve device performance by engineering the local strong EM field to enhance the light–matter interaction at the nanoscale [1, 3, 5]. Overall, these works provide unique approaches for energy-efficient on-chip plasmonic circuitry for next-generation optical communication, computation, and quantum information processing. The detailed mechanisms and potential applications of this technology will be explored further in the presentation.

Reference
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Keywords: 2D materials, Plasmonics, Exciton–Polariton , Photodetectors, Transition Metal Nitrides