Semester Projects

Semester Projects (Fall semester 2020-2021)

All projects can be adapted for a Bachelor or a Master level

New fabrication methods for metallic and all-dielectric nano-object arrays

Metallic nano-objects and their arrays exhibit peculiar functionalities that can be exploited in several scientific fields. Such constructs can indeed be used as catalysts for arrays of semiconducting nanowires, in light trapping and extraction systems, as efficient transparent electrodes for optoelectronic devices, and in sensing and biological applications. Their fabrication remain however difficult and costly, especially over large area substrates. In this project we propose to investigate a novel fabrication approach of these nano-structures that is simple and scalable. The objective is to demonstrate a 2D and a 3D ordered array of nano-objects using simple nano-imprint and thin-film processing approaches.

Influence of the composition of polymer nanocomposites on their electrical and rheological properties for multimaterial fibre devices

Thermally drawn multimaterial fibres developed for optoelectronic applications often employ polymer nanocomposites as electrode materials, because they are compatible with the thermal drawing process thanks to their thermoplastic properties [1]. However, the conductivity of such composites is far from that of metals, and even if increasing the concentration of fillers can improve it, there is a limit at which the composite loses its appropriate rheological attributes [2]. Both the conductivity and this limit strongly depend on the morphology of the particles and how they are dispersed in the polymer matrix. In this project, the conductivity and rheological properties of nanocomposites with different fillers made from melt mixing and solution techniques will be investigated. The student will learn techniques to make polymer nanocomposites via liquid processes, to fabricate multimaterial fibers and characterize their thermomechanical, optical and electronic properties.

Experimental and modelling tools:

  • Nanocomposite fabrication by melt mixing and solution techniques
  • Multimaterial preform fabrication and thermal drawing technique
  • Optical, electronic and rheological properties

[1] S. Egusa, et al. Multimaterial piezoelectric fibres. Nat Mater, 9 (2010) 643.

[2] J. A. King, et al. Electrical conductivity and rheology of carbon-filled liquid crystal polymer composites, J Appl Polym Sci., 101(2006) 2680.

Novel fabrication approaches of semiconducting nanowire meshes

Optoelectronic devices, in which the active materials are semiconductors, are typically made using energy-intensive processes. Studies conducted in FIMAP have shown that low-cost nano-imprinting and physical vapor deposition techniques followed by a simple heat treatment can lead to well-defined arrays of nano-spheres of semiconductor. Characterisation of this nano-structure have revealed peculiar light absorption properties, which means it can be used as the building block of a photodetecting device. The aim of this project is therefore to combine this process with embossing and other deposition techniques to create such a device. The student will use nano-imprinting as well as thin-film deposition techniques, and learn optical characterization approaches of semiconducting nano-structures.

Experimental and modelling tools:

  • Thin film fabrication and nano-imprinting
  • Thermal treatment
  • Optoelectronic characterization
  • Materials characterization (SEM)

Pressure-Sensing fiber devices

Pressure-sensing flexible systems have drawn a lot of attention due to their wide applications in touch displays, electronic skin, health care and biomonitoring (such as pulse wave monitoring), etc. Several approaches have been proposed in recent years, such as microstructured polydimethylsiloxane films which are integrated into the gates of an array of organic field-effect transistor [1,2] and artificial skin[3]. However, these approaches are complex and costly, and especially hard to realize over large scales. In this project, we propose a novel, high efficiency, and low-cost strategy to fabricate large scale fiber devices that can be sensitive to pressure. Thermal drawing will be a preferred method to fabricate the fibers and different kinds of materials, such as metal, polymer and carbon materials will be combined to achieve the targeted functionalities. The main aim of this project is to optimize the fiber devices with respect to its structure, the material selection and processing parameters. Students will learn about pressure-sensing devices design, fiber fabrication methods as well as structural and electronic characterization tools.

Experimental and modelling tools:

  • Multi-material perform fabrication and thermally drawn technique
  • Electronic characterization
  • Mechanical properties characterization (viscosity, etc.)
  • Materials characterization (Optical Microscopy, SEM)

[1] S.C.B Mannsfeld, et al. Highly sensitive flexible pressure sensors with microstructured rubber dielectric layers. Nat Mater, 9(2010) 859.

[2] G. Schwartz, et al. Flexible polymer transistors with high pressure sensitivity for application in electronic skin and health monitoring. Nat Commun, 4(2013) 1859.

[3] D. Kim, et al. Epidermal electronics. Science, 333(2011)838.

Thermal drawing Technique for Large-Area Functional Surfaces

Thermal Drawing Technique has been demonstrated as an ideal Method for microfabrication [1][2][3]. Based on an approach developed in FIMAP, the micron and even sub-micron structures have been deployed on the surface of fibers and ribbons, and even on the internal surface of hollow-core fibers. This development has brought tremendous interest in various fields, from optics, optoelectronic to biology. The proposed project aims to establish the Thermal Drawing Technique for Large-Area Functional Surface, by fabrication a new type of preforms and by evaluating the surface adhesion of different polymers.

Experimental and modelling tools:

  • Multi-material perform fabrication and thermally drawn technique
  • Rheological measurement
  • Surface adhesion characterization

[1] Nguyen-Dang et al, Advanced Functional Materials, 27, 1605935 (2017).

[2] Nguyen-Dang, Page et al, Journal of Physics D: Applied Physics, 50, 144001 (2017)

[3] Yan et al, Advanced Materials, on line: 10.1002/adma.201700681 (2017).

Generating light with nanostructures

Non-linear second or third harmonic light generation is of significant relevance in many integrated optical circuits today. Efficient signal conversion can open up new possibilities in optical computation or supercontinuum generation.

Controlled dewetting provides an interesting and efficient way to obtain ordered nanostructures of various optical materials. This process can be an efficient platform to enhance second or third order harmonics  for strong incident light beams. Beyond dewetted structures, this project will also focus on non linear light generation in particular monocrystalline systems.

Experimental :

  • Thermal Evaporation
  • Nanoimprint techniques
  • Optical Characterization

Basic but no advanced knowledge in optics is required at the start of this project.

If you are interested and want to learn more about these projects please contact Prof. Sorin.