Periodic Reporting for period 2 - INTRINSIC (INducing TRionic gaIn in two-dimensional semicoNductors by local StraIn and Charge manipulation)
Période du rapport: 2024-11-01 au 2025-10-31
The INTRINSIC project (INducing TRionic gaIn in two-dimensional semicoNductors by local StraIn and Charge manipulation) aims to advance excitonic-based optoelectronic devices by controlling excitonic complexes, such as excitons and trions, in 2D semiconductors, particularly transition metal dichalcogenides (TMDCs). The project seeks to achieve precise exciton-to-trion conversion, enabling trionic optical gain and lasing — a mechanism relying on intrinsic exciton-trion interactions upon photoexcitation rather than global population inversion.
To accomplish this, INTRINSIC investigates how excitonic complexes form in TMDCs under morphological and dielectric changes. It focuses as well on designing open optical cavities that can induce both (i) charge confinement effects through strain or charge doping, promoting exciton-to-trion conversion and (ii) laser feedback in targeted spectral regions.
To accomplish this, INTRINSIC investigates how excitonic complexes form in TMDCs under morphological and dielectric changes. It focuses as well on designing open optical cavities that can induce both (i) charge confinement effects through strain or charge doping, promoting exciton-to-trion conversion and (ii) laser feedback in targeted spectral regions.
During the first reporting period, training activities included (i) the exfoliation and characterization of TMDC monolayers and flakes using optical contrast microscopy, photoluminescence micro-spectroscopy, and atomic force microscopy (ii) dry-transfer technique to transfer TMDCs monolayer between different substrates comprising transfer of a TMDC monolayer on a TMDC nanostructured flake, (iii) use of a custom-built optical microscope with spectroscopic capabilities for measuring polarization resolved (both excitation and detection) k-space transmission/reflection and photoluminescence (iv) training on the spectroscopic characterization of laser emission with k-space spectroscopy, (v) procedure for preparing TMDC flakes for electron beam lithography. Supported by Rigorous Coupled Wave Analysis simulations, we designed and fabricated an all-TMDC vertical heterostructure capable of sustaining high-quality-factor photonic resonances. The tunability of these photonic resonances, achieved through precise modification of the heterostructure's geometric parameters, has resulted in altered emission properties. These changes, potentially induced by modifications in the dielectric environment and strain fields, will be key features in achieving trionic lasing. The researcher also published two peer-reviewed journal articles, and delivered to group members four presentation highlighting the results of the research work. The implementation of the INTRINSIC project during the first reporting period has significant improved the researcher’s career prospects by offering a wide range of new skills ranging from advanced nanofabrication, spectroscopic characterization and electromagnetic simulation of nanophotonic devices.
During the second reporting period (return phase), the project activities focused on consolidating the main scientific outcomes and establishing durable experimental capability at the return host. An electromagnetic-modelling framework (including RCWA-based analysis) was applied to provide a consistent interpretation of the photonic modes of photonic crystal gratings and their impact on monolayer emission in k-space, including the spectral region relevant to trion emission, and to identify practical strategies to further increase the grating quality factor to strengthen the observed enhancement. In parallel, a custom micro-spectroscopy system was designed, installed at the host institution, enabling optical characterisation of two-dimensional materials (including laser-emission measurements) and supporting reproducibility and continuity beyond the fellowship.
During the second reporting period (return phase), the project activities focused on consolidating the main scientific outcomes and establishing durable experimental capability at the return host. An electromagnetic-modelling framework (including RCWA-based analysis) was applied to provide a consistent interpretation of the photonic modes of photonic crystal gratings and their impact on monolayer emission in k-space, including the spectral region relevant to trion emission, and to identify practical strategies to further increase the grating quality factor to strengthen the observed enhancement. In parallel, a custom micro-spectroscopy system was designed, installed at the host institution, enabling optical characterisation of two-dimensional materials (including laser-emission measurements) and supporting reproducibility and continuity beyond the fellowship.
Within the INTRINSIC project, we have developed an all-TMDCs photonic platform based on a vertical heterostructure that can induce modifications to the emission properties of one of its constituents at room temperature. We anticipate that these photonic heterostructures, along with possible modifications to enhance the quality factor of the photonic resonances, will be crucial for achieving trionic lasing. This process holds significant promise for the development of ultrathin, low-power demanding emission devices, aligning with efforts to reduce energy consumption.
These results represent an advance over the state of the art in 2D-material nanophotonics by demonstrating a fully 2D-material-based (“all-TMDC”) architecture that enables room-temperature control of emission through engineered photonic modes, without relying on hybrid integration with conventional high-index dielectric photonic structures. The platform provides a compact and design-tunable route to tailor radiative properties (including dispersion and outcoupling in momentum space) and offers a systematic basis to optimize geometry-dependent resonance features (including quality factor) to further strengthen emission enhancement.
These results represent an advance over the state of the art in 2D-material nanophotonics by demonstrating a fully 2D-material-based (“all-TMDC”) architecture that enables room-temperature control of emission through engineered photonic modes, without relying on hybrid integration with conventional high-index dielectric photonic structures. The platform provides a compact and design-tunable route to tailor radiative properties (including dispersion and outcoupling in momentum space) and offers a systematic basis to optimize geometry-dependent resonance features (including quality factor) to further strengthen emission enhancement.