Graphene nanostructuring for energy conversion at nanoscale

Oct 13, 2023 | Stages, thèses

a) Scanning electron microscope image of a graphene-based nanostructured device for electric and thermoelectric measurements.

b) Absolute value of the Seebeck coefficient for nanostructured (bleu data) and pristine (pink data) multilayer graphene.

Laboratoire: MPQ (Matériaux et Phénomènes Quantiques), Université Paris Cité & CNRS
Adresse: Bâtiment Condorcet – 10 rue A. Domon et L. Duquet – 75013 Paris
Directeur de stage/thèse: Maria Luisa DELLA ROCCA
Tel: 01 57 27 70 13
e-mail: maria-luisa.della-rocca@u-paris.fr

Scientific project:

Research on new thermoelectric (TE) devices and materials for thermal management at nanoscale is highly demanded in nanoelectronics. In particular, energy conversion of TE nanogenerators aims to recover waste heat in nanoelectronics, improving device performances. Following this objective, the TE efficiency ZT, defined as ZT=S2sT/k (with S the Seebeck coefficient, s the electrical conductivity, k the thermal conductivity and T the temperature) is the relevant parameter that researchers struggle to improve. Active TE materials must have low thermal conductivity and high electrical conductivity, which is an antonymic behavior in common bulk materials but it can be achieved in nanostructured systems1. The discovery of 2D materials has open new routes of investigation in this domain, high ZT values have been predicted in graphene nanostructure2 and transition metal dicalcogenides (TMD) have revealed high Seebeck coefficients3.

The main goal of the internship is to experimentally investigate the electric (s), thermoelectric (S) and thermal properties (k) of devices based on nanostructured graphene. Nanostructuring will be engineered by a network of holes, with 300-400nm diameter and 50-150nm edge width, aiming to reduce the phonon mean free path without affecting significantly the electron mean free path. The students will be involved in sample fabrication in clean room (dry transfer of the 2D material, e-beam lithography, etching, metal deposition …), electrical measurements (s, S) and modulated thermoreflectance measurements (k) (coll. INSP – Paris). The team has recently demonstrated the ability of achieving a complete thermoelectrical characterization of 2D materials-based devices4,5 and has already achieved promising preliminary results (see Fig.). The team’s expertise in the investigation of charge and spin transport in 2D materials and in clean room micro and nano fabrication techniques will be exploited in the project.
 
 
 
 

[1] A. Principi and G. Vignale, Phys. Rev. Lett. 115, 056603 (2015)
[2] P. Dollfus et al., J. Phys.: Condens. Matter 27, 133204 (2015)
[3] M. Buscema et al., Nano. Lett. 13, 358 (2013)
[4] S. Timpa et al., J. Appl. Phys. 130, 185102 (2021)
[5] M. Rahimi et al., Phys. Rev. Appl. 19, 034075 (2023) 


Methods and techniques: micro‐fabrication in clean room, transport/optical measurements
Possibility to go on with a PhD: YES
Envisaged fellowship: EDPIF competition and/or PhD funding request submitted in projects

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