Laboratoire Charles Coulomb (L2C)

Stages M1 et M2

Engineering Long-Lived Catalysts
for Dense and Ultralong Single-Walled Carbon Nanotube Arrays

Context:
Single-walled carbon nanotubes (SWCNTs) combine exceptional electrical, mechanical and chemical properties, making them promising building blocks for next-generation nanoelectronics, such as low-power-consumption transistors and flexible and transparent electronics. Yet their integration into large-scale technologies remains limited by the difficulty of producing nanotube arrays with simultaneously high density, long length and controlled electronic properties. Next-generation SWCNT technologies critically depend on a standardized
“nanotube wafer” with well-controlled properties, similar to silicon wafers, to enable scalable and high-performance device fabrication. The target is a wafer featuring high-density, ultralong arrays of SWCNTs with a high fraction of semiconducting nanotubes. This is the objective of the MENDEL consortium (2027-2030) composed of Laboratory Charles Coulomb in Montpellier and
Laboratory MEM at CEA Grenoble, and funded by the French National Research Agency (ANR).

A major challenge is that the catalyst nanoparticles progressively lose their activity during growth, limiting the length and density of the resulting nanotube arrays. The central question is how the composition and thickness of ultrathin catalyst layers influence catalyst lifetime during CVD growth, and how this ultimately affects the density and length of the resulting SWCNT arrays. Understanding and controlling catalyst deactivation is therefore a key step toward
achieving ultralong and dense SWCNT arrays.

During the internship, you will develop hands-on expertise in thin-film deposition, catalyst engineering, CVD growth of CNTs, and advanced characterization techniques. You will prepare ultrathin catalyst systems using state-of-the-art deposition techniques, grow horizontally aligned CNT arrays by CVD, and characterize individual nanotubes using charge-contrast SEM, AFM, and resonant Raman spectroscopy. The project will also involve quantitative analysis and image
processing of the SEM, AFM and Raman data to establish correlations between catalyst properties and CNT growth. You will systematically investigate how catalyst composition and thickness influence catalyst lifetime, with the aim of achieving longer nanotubes while maintaining high growth density.

You will be fully immersed in hands-on experimental research within the Nanomaterials team of L2C, working closely with two researchers specialized in carbon nanotube growth and characterization and interacting regularly with researchers from the MENDEL consortium.
The internship may lead to a PhD opportunity within the MENDEL project, subject to performance and funding.

Who should apply?

  • Master 2 students in Physics, Chemistry, Materials Science, Nanoscience, or related field
  • A strong interest in experimental research and nanomaterials
  • Interest in materials synthesis, surface science, catalysis, or nanotechnology
  • A rigorous and autonomous approach to experimental work
  • Good communication skills in English
  • Previous experience in experimental research or nanofabrication is appreciated but not required

Application date: open until the position is filled.
Starting date: between January and March 2027.

Internship supervisors:

Application details:

The candidate must send:

  • a personalized motivation letter detailing his/her interest and matching for the project
  • the transcripts of marks of Bachelor / Licence and Master 1
  • a detailed CV (education, coursework, and previous research experience)
  • the contact details of 2-3 academic or research referees.
    Incomplete applications will not be considered.
Spin Dynamics and Magnetic Interactions in Lead
Halide Perovskites: A Spin Noise Spectroscopy
Approach

Context:
Lead halide perovskites (such as MAPbI3, FAPbI3, CsPbBr3) have emerged as a revolutionary class of materials in optoelectronics due to their exceptional properties: strong light absorption, long carrier diffusion lengths, and ease of synthesis [1]. These materials are already widely used in high-efficiency solar cells, LEDs, and light detectors. However, their magnetic and spin properties, which could be crucial for applications in spintronics and quantum technologies, remain largely unexplored.


Lead halide perovskites have a unique crystalline structure where interactions between lead ions ( Pb2+), halogens ( I−, Br−, Cl−), and organic cations (such as MA+ or FA+) can influence spin dynamics. In particular, spin-orbit effects, hyperfine couplings, and exchange interactions in these materials may play a key role in spin relaxation and carrier coherence [2, 3, 4]. These properties are essential for the development of innovative devices such as magnetic memories,
spin transistors, or qubits.


Spin noise spectroscopy (SNS) is a particularly suitable technique for studying these mechanisms [5, 6]. Unlike traditional methods (such as pump-probe Faraday rotation spectroscopy or magneto-optical techniques like the Hanle effect in photoluminescence), SNS allows probing intrinsic spin fluctuations while minimizing absorption and avoiding system perturbation. This approach is ideal for studying spin relaxation times ( T1 and T2), spin diffusion lengths, and
spin-spin interactions to understand decoherence mechanisms.


Currently, there are very few studies on perovskites using SNS [2]. Our group has very recently started working in this direction, and obtained the first results bringing new insights on spatial distribution of spin carriers in MAPbI3 single crystals. The objective of the internship is to extend this work on MA1−xFAxPb3 alloys, to understand how the disorder induced by variation of organic cation affects carrier localization volumes and the resulting spin coherence times. SNS measurements could be combined with the development of theoretical models.


The student will benefit from the experience of the host team in physics of semiconductors nanostructures and a high-performance experimental setup implementing homodyne detection and allowing numerous adaptations. The samples are available through established external collaborations.


We are looking for a motivated student interested in optical experiments, with a background in semiconductor physics, quantum mechanics, and optics. Fluency in English is required, while proficiency in French is not mandatory but a strong motivation to learn is necessary. The internship is intended to be followed by a PhD thesis, provided that the necessary funding can be secured.

Contact

maria.vladimirova@umontpellier.fr

steeve.cronenberger@umontpellier.fr
References
[1] Hybrid Organic Inorganic Perovskites: Physical Properties and Applications. Eds. Z. V. Vardeny and M. C. Beard (World Scientific, Singapore, 2022).
[2] Spin noise reveals spin dynamics and recharging of lead halide perovskite nanocrystals, V.O. Kozlov et al, Applied Materials Today 45, 102820 (2025).
[3] Resonant Spin Amplification and Accumulation in MAPbI3 Single Crystals, E. Kirstein etal, Advanced Science 12, 2502735 (2025).
[4] Spin Coherence and Relaxation Dynamics of Localized Electrons and Holes in FAPbI3 Films, G. Lagüe et al, ACS Photonics 11, 2770 (2024).
[5] Spin noise of localized electrons in CdTe/CdMgTe quantum well, A. L. Zibinskiy et al, Phys. Rev. B 113, 205418 (2026).
[6] Angle-resolved spin noise spectroscopy in semiconductors: Two-state theory and experiments, Gribakin et al, Physical Review Research 7, 013222 (2025).