arXiv subjects

Cédric Lemieux-Leduc

Publications and source records attributed to Cédric Lemieux-Leduc.

5 recordsLinked to original sources

arXiv2026

Mid-Infrared Thermal Radiation Harvesting using Uncooled Narrow Bandgap GeSn Thermophotovoltaic cell

Thermophotovoltaic (TPV) cells are increasingly attractive for applications in industrial waste heat harvesting, aerospace energy management, and compact power generation. Deploying midwave-infrared (MWIR) TPV in practical applications requires narrow-bandgap semiconductors that not only absorb low-energy photons but also integrate with scalable, low-cost platforms. Although high-performance TPV devices have been demonstrated using III-V materials such as InAs, GaSb, and InGaAs(P), their use remains limited by cost and substrate size. With this perspective, narrow bandgap GeSn alloys are a promising alternative that extend group-IV absorption into the MWIR while being silicon-compatible. Although the potential of GeSn TPV cells has been predicted, no experimental demonstration has been reported. Here, proof-of-concept Ge$_{0.91}$Sn$_{0.09}$ p-i-n TPV diodes (1 mm diameter) grown on silicon were fabricated and their performance was benchmarked against commercial InAs and extended-InGaAs devices. Measurements at 300 K under 2.33 $μ$m laser and $\sim$1500 K SiC Globar illumination revealed peak responsivity of $\sim$ 0.2 A/W at $\sim$ 1.7 $μ$m, and an output power of $\sim$ 0.41 mW/cm$^2$. These devices show trends comparable to those of the InAs diode under identical conditions, although at reduced absolute levels. To assess the intrinsic performance potential, Poisson-drift-diffusion modeling incorporating experimentally calibrated emitter emissivity predicts power densities exceeding 1 W/cm$^2$ under moderate MWIR thermal illumination, indicating that the present devices operate far below their fundamental limits and are primarily constrained by defect-assisted recombination and transport losses. These results establish GeSn as a scalable, silicon-compatible MWIR TPV platform and highlight a larger performance potential achievable through material and device optimization.

physics.app-ph↗

arXiv2025

Polarization-sensitive GeSn Mid-Infrared Membrane Photodetectors with Integrated Plasmonic Metasurface

Germanium-Tin (GeSn) semiconductors are promising for mid-infrared optoelectronics owing to their silicon compatibility, tunable bandgap, and potential for room-temperature operation. Released GeSn membranes provide an additional degree of freedom to extend the operation wavelength through epitaxial strain relaxation, while their transferability expands design flexibility. On the other hand, metasurfaces have become an effective strategy to engineer light--matter interaction, and their integration with photodetectors can enhance performance and introduce new functionalities. Here, we demonstrate a mid-infrared photodetector consisting of a transfer-printed Ge$_{0.89}$Sn$_{0.11}$ membrane integrated with an Au plasmonic metasurface. The photodetector exhibits a wavelength cutoff exceeding 3.0~$μ$m with nearly fourfold increase in responsivity at 2.5~$μ$m as compared to unreleased films, attributed to Fabry--Pérot resonance. Furthermore, the integration with an anisotropic metasurface yields detectors with strong polarization sensitivity, achieving a measured contrast ratio of $\sim$4:1 between orthogonal polarizations. Moreover, the operation wavelength of the photodetector can be selectively tuned by varying the geometric scale of the metasurface. The experimental results show excellent agreement with simulations, confirming the effectiveness and versatility of this integrated metasurface--membrane design.

physics.app-ph↗

arXiv2025

Waveguide-Coupled Mid-Infrared GeSn Membrane Photodetectors on Silicon-on-Insulator

Silicon photonics has thrived in telecommunications over recent decades, and its extension to the mid-infrared range has the potential to unlock valuable opportunities for sensing, imaging, and free-space communications. With this perspective, germanium-tin (GeSn) alloy has been extensively investigated as a silicon-compatible semiconductor with bandgap tunability that covers this entire spectral range. Indeed, a variety of GeSn-based high-performance optoelectronic devices have been demonstrated, confirming the potential of this system for mid-infrared applications. However, the integration of these devices onto silicon photonic platforms remains underexplored. Herein, we demonstrate the fabrication and integration, through transfer-printing, of strain-relaxed GeSn membranes onto silicon-on-insulator waveguides to create integrated detectors operating up to 3.1 $μ$m at room temperature. Two different designs of waveguide structures are evaluated to study the coupling efficiency between the passive structures and the active membrane detector. A responsivity reaching 0.36 A/W at an operation wavelength of 2.33 $μ$m is measured under a bias of 1 V. Moreover, the fabrication resulted in multiple working devices exhibiting similar performance using a single transfer printing step, demonstrating the scalability of the proposed approach.

physics.app-ph↗

arXiv2024

Transfer-printed multiple Ge$_{0.89}$Sn$_{0.11}$ membrane mid-infrared photodetectors

Due to their narrow band gap and compatibility with silicon processing, germanium-tin (Ge$_{1-x}$Sn$_x$) alloys are a versatile platform for scalable integrated mid-infrared photonics. These semiconductors are typically grown on silicon wafers using Ge as an interlayer. However, the large lattice mismatch in this heteroepitaxy protocol leads to the build-up of compressive strain in the grown layers. This compressive strain limits the material quality and its thermal stability besides expanding the band gap, thereby increasing the Sn content needed to cover a broader range in the mid-infrared. Released Ge$_{1-x}$Sn$_x$ membranes provide an effective way to mitigate these harmful effects of the epitaxial strain and control the band gap energy while enabling the hybrid integration onto different substrates. With this perspective, herein strain-relaxed Ge$_{0.89}$Sn$_{0.11}$ membranes are fabricated and subsequently transfer-printed with metal contacts to create multiple photodetectors in a single transfer step. The resulting photodetectors exhibit an extended photodetection cutoff reaching a wavelength of $3.1 \,μ$m, coupled with a significant reduction in the dark current of two orders of magnitude as compared to as-grown photoconductive devices. The latter yields a reduced cutoff of $2.8 \,μ$m due to the inherent compressive strain. Furthermore, the impact of chemical treatment and annealing on the device performance was also investigated showing a further reduction in the dark current. The demonstrated transfer printing, along with the use of an adhesive layer, would allow the transfer of multiple GeSn membranes onto virtually any substrate. This approach paves the way for scalable fabrication of hybrid optoelectronic devices leveraging the tunable band gap of Ge$_{1-x}$Sn$_x$ in the mid-wave infrared range.

physics.app-ph↗

arXiv2022

Micrometer-thick, atomically random Si0.06Ge0.90Sn0.04 for silicon-integrated infrared optoelectronics

A true monolithic infrared photonics platform is within reach if strain and bandgap energy can be independently engineered in SiGeSn semiconductors. Herein, we investigate the structural and optoelectronic properties of a 1.5 μm-thick Si0.06Ge0.90Sn0.04 layer that is nearly lattice-matched to a Ge on Si substrate. Atomic-level studies demonstrate high crystalline quality and uniform composition and show no sign of short-range ordering and clusters. Room temperature spectroscopic ellipsometry and transmission measurements show direct bandgap absorption at 0.83 eV and a reduced indirect bandgap absorption at lower energies. Si0.06Ge0.90Sn0.04 photoconductive devices operating at room temperature exhibit dark current and spectral responsivity (1 A/W below 1.5 μm wavelengths) similar to Ge on Si devices, with the advantage of a near-infrared band gap tunable by alloy composition. These results underline the relevance of SiGeSn semiconductors in implementing a group IV material platform for silicon-integrated infrared optoelectronics.

cond-mat.mtrl-sci↗