Mickael L. Perrin

Last Name

Perrin

First Name

Mickael L.

ORCID

0000-0003-3172-889X

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09782 - Perrin, Mickaël / Perrin, Mickaël

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Publications 1 - 10 of 16

Redox-controlled conductance of polyoxometalate molecular junctions
Huez, Cécile; Guérin, David; Lenfant, Stéphane; et al. (2022)
Nanoscale
We demonstrate the reversible in situ photoreduction of molecular junctions of a phosphomolybdate [PMo12O40](3-) monolayer self-assembled on flat gold electrodes, connected by the tip of a conductive atomic force microscope. The conductance of the one electron reduced [PMo12O40](4-) molecular junction is increased by similar to 10, and this open-shell state is stable in the junction in air at room temperature. The analysis of a large current-voltage dataset by unsupervised machine learning and clustering algorithms reveals that the electron transport in the pristine phosphomolybdate junctions leads to symmetric current-voltage curves, controlled by the lowest unoccupied molecular orbital (LUMO) at 0.6-0.7 eV above the Fermi energy with similar to 25% of the junctions having a better electronic coupling to the electrodes than the main part of the dataset. This analysis also shows that a small fraction (similar to 18% of the dataset) of the molecules is already reduced. The UV light in situ photoreduced phosphomolybdate junctions systematically feature slightly asymmetric current-voltage behaviors, which is ascribed to the electron transport mediated by the single occupied molecular orbital (SOMO) nearly at resonance with the Fermi energy of the electrodes and by a closely located single unoccupied molecular orbital (SUMO) at similar to 0.3 eV above the SOMO with a weak electronic coupling to the electrodes (similar to 50% of the dataset) or at similar to 0.4 eV but with a better electrode coupling (similar to 50% of the dataset). These results shed light on the electronic properties of reversible switchable redox polyoxometalates, a key point for potential applications in nanoelectronic devices.
Double quantum dots in atomically-precise graphene nanoribbons
Zhang, Jian; Qian, Liu; Barin, Gabriela Borin; et al. (2023)
Materials for Quantum Technology
Bottom-up synthesized graphene nanoribbons (GNRs) are precise quantum materials, offering a high degree of tunability of their physical properties. While field-effect transistors and single quantum dot (QD) devices have been reported, the fabrication of double QD devices using GNRs remains challenging due to their nanometer-scale dimensions. In this study, we present a multi-gate double QD device based on atomically precise GNRs that are contacted by a pair of single-walled carbon nanotube electrodes. At low temperatures, the device can be tuned with multiple gates and reveals triangular features characteristic for charge transport through a double QD system. From these features, the QD level spacing, as well as the interdot tunnel coupling and lead-dot tunnel couplings are extracted. Double QD systems serve as essential building blocks for developing different types of qubits based on atomically precise GNRs.
High-speed identification of suspended carbon nanotubes using Raman spectroscopy and deep learning
Zhang, Jian; Perrin, Mickael L.; Barba, Luis; et al. (2022)
Microsystems & Nanoengineering
The identification of nanomaterials with the properties required for energy-efficient electronic systems is usually a tedious human task. A workflow to rapidly localize and characterize nanomaterials at the various stages of their integration into large-scale fabrication processes is essential for quality control and, ultimately, their industrial adoption. In this work, we develop a high-throughput approach to rapidly identify suspended carbon nanotubes (CNTs) by using high-speed Raman imaging and deep learning analysis. Even for Raman spectra with extremely low signal-to-noise ratios (SNRs) of 0.9, we achieve a classification accuracy that exceeds 90%, while it reaches 98% for an SNR of 2.2. By applying a threshold on the output of the softmax layer of an optimized convolutional neural network (CNN), we further increase the accuracy of the classification. Moreover, we propose an optimized Raman scanning strategy to minimize the acquisition time while simultaneously identifying the position, amount, and metallicity of CNTs on each sample. Our approach can readily be extended to other types of nanomaterials and has the potential to be integrated into a production line to monitor the quality and properties of nanomaterials during fabrication.
Spatially mapping thermal transport in graphene by an opto-thermal method
Braun, Oliver; Furrer, Roman; Butti, Pascal; et al. (2022)
npj 2D Materials and Applications
Mapping the thermal transport properties of materials at the nanoscale is of critical importance for optimizing heat conduction in nanoscale devices. Several methods to determine the thermal conductivity of materials have been developed, most of them yielding an average value across the sample, thereby disregarding the role of local variations. Here, we present a method for the spatially resolved assessment of the thermal conductivity of suspended graphene by using a combination of confocal Raman thermometry and a finite-element calculations-based fitting procedure. We demonstrate the working principle of our method by extracting the two-dimensional thermal conductivity map of one pristine suspended single-layer graphene sheet and one irradiated using helium ions. Our method paves the way for spatially resolving the thermal conductivity of other types of layered materials. This is particularly relevant for the design and engineering of nanoscale thermal circuits (e.g. thermal diodes).
Determining the Number of Graphene Nanoribbons in Dual-Gate Field-Effect Transistors
Zhang, Jian; Barin, Gabriela Borin; Furrer, Roman; et al. (2023)
Nano Letters
Bottom-up synthesized graphene nanoribbons (GNRs) are increasingly attracting interest due to their atomically controlled structure and customizable physical properties. In recent years, a range of GNR-based field-effect transistors (FETs) has been fabricated, with several demonstrating quantum-dot (QD) behavior at cryogenic temperatures. However, understanding the relationship between the cryogenic charge-transport characteristics and the number of the GNRs in the device is challenging, as the length and location of the GNRs in the junction are not precisely controlled. Here, we present a methodology based on a dual-gate FET that allows us to identify different scenarios, such as single GNRs, double or multiple GNRs in parallel, and a single GNR interacting with charge traps. Our dual-gate FET architecture therefore offers a quantitative approach for comprehending charge transport in atomically precise GNRs.
Contacting atomically precise graphene nanoribbons for next-generation quantum electronics
Zhang, Jian; Calame, Michel; Perrin, Mickael L. (2022)
Matter
Exploring atomically precise graphene nanoribbons (GNRs) for quantum technology purposes does not only require control over their chemical structure, but also preservation of their properties upon integration into devices. We briefly discuss here existing contacting strategies for nanometer-sized GNRs and discuss possible future device architectures.
Influence of Peripheral Alkyl Groups on Junction Configurations in Single-Molecule Electronics
Ornago, Luca; Zwick, Patrick; van der Poel, Sebastiaan; et al. (2024)
The Journal of Physical Chemistry C
The addition of a lateral alkyl chain is a well-known strategy to reduce pi-stacked ensembles of molecules in solution, with the intention to minimize the interactions between the molecules' backbones. In this paper, we study whether this concept generalizes to single-molecule junctions by using a combination of mechanically controllable break junction (MCBJ) measurements and clustering-based data analysis with two small series of model compounds decorated with various bulky groups. The systematic study suggests that introducing alkyl side chains also favors the formation of electrode-molecule configurations that are not observed in their absence, thereby inducing broadening of the conductance peak in the one-dimensional histograms. Thus, the introduction of alkyl chains in aromatic compounds for molecular electronics must be carefully designed and optimized for the specific purpose, balancing between increased solubility and the possibility of additional junction configurations.
Exciton-assisted electron tunnelling in van der Waals heterostructures
Wang, Lujun; Papadopoulos, Sotirios; Iyikanat, Fadil; et al. (2023)
Nature Materials
The control of elastic and inelastic electron tunnelling relies on materials with well-defined interfaces. Two-dimensional van der Waals materials are an excellent platform for such studies. Signatures of acoustic phonons and defect states have been observed in current-to-voltage measurements. These features can be explained by direct electron–phonon or electron–defect interactions. Here we use a tunnelling process that involves excitons in transition metal dichalcogenides (TMDs). We study tunnel junctions consisting of graphene and gold electrodes separated by hexagonal boron nitride with an adjacent TMD monolayer and observe prominent resonant features in current-to-voltage measurements appearing at bias voltages that correspond to TMD exciton energies. By placing the TMD outside of the tunnelling pathway, we demonstrate that this tunnelling process does not require any charge injection into the TMD. The appearance of such optical modes in electrical transport introduces additional functionality towards van der Waals material–based optoelectronic devices.
Electronic confinement induced quantum dot behavior in magic-angle twisted bilayer graphene
Ghawri, Bhaskar; Bastante, Pablo; Watanabe, Kenji; et al. (2025)
Nanoscale
Magic-angle twisted bilayer graphene (TBLG) has emerged as a versatile platform to explore correlated electron phases driven primarily by low-energy flat bands in moiré superlattices. While techniques for controlling the twist angle between graphene layers have spurred rapid experimental progress, understanding the effects of doping inhomogeneity on electronic transport in correlated electron systems remains challenging. In this work, we investigate the interplay of confinement and doping inhomogeneity on the electrical transport properties of TBLG by leveraging device dimensions and twist angles. We show that reducing device dimensions can magnify disorder potentials caused by doping inhomogeneity, resulting in pronounced carrier confinement. This phenomenon is evident in charge transport measurements, where the Coulomb blockade effect is observed. Temperature-dependent measurements reveal a large variation in the activation gap across the device. These findings highlight the critical role of doping inhomogeneity in TBLG and its significant impact on the transport properties of the system.
Electric field tunable bandgap in twisted double trilayer graphene
Perrin, Mickael L.; Jayaraj, Anooja; Ghawri, Bhaskar; et al. (2024)
npj 2D Materials and Applications
Twisted van der Waals heterostructures have recently emerged as a versatile platform for engineering interaction-driven, topological phenomena with a high degree of control and tunability. Since the initial discovery of correlated phases in twisted bilayer graphene, a wide range of moiré materials have emerged with fascinating electronic properties. While the field of twistronics has rapidly evolved and now includes a range of multi-layered systems, moiré systems comprised of double trilayer graphene remain elusive. Here, we report electrical transport measurements combined with tight-binding calculations in twisted double trilayer graphene (TDTLG). We demonstrate that small-angle TDTLG (~1.7−2.0∘) exhibits an intrinsic bandgap at the charge neutrality point. Moreover, by tuning the displacement field, we observe a continuous insulator-semimetal-insulator transition at the CNP, which is also captured by tight-binding calculations. These results establish TDTLG systems as a highly tunable platform for further exploration of magneto-transport and optoelectronic properties.

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Mickael L. Perrin

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