Mario COSTANZA : "Integration of graphene on micro-acoustic radiofrequency components"

Abstract : The acoustoelectronic interaction of mobile carriers with acoustic waves is a phenomenon at the heart of the electronic properties of materials. For several years, this non-linear interaction has been at the heart of developments intended to manipulate the response of electronic or photonic devices with acoustic waves. In particular, two-dimensional materials, such as graphene, have the potential to improve the response of non-linear microacoustic devices due to their high mobility and low mass.
The objective of this thesis was then to demonstrate that a graphene architecture on lithium niobate for surface acoustic wave devices makes it possible to produce a functional convolver device operating at several GHz. For this, the transfer of graphene onto lithium niobate was optimized in a clean room. The transferred films were characterized electrically, by classical and quantum Hall measurements as well as by Raman spectroscopy. The results showed that we obtained p-type doped transferred graphene films. Characterizations of the acoustoelectronic current on micro-acoustic surface waves components at 2.5 GHz confirmed strong coupling. Finally, non-degenerate amplifiers and convolvers based on the acoustoelectronic effect were developed. The results show a high sensitivity of the devices with the heating induced at high acoustic power of which the amplifiers are particularly sensitive. The convolution effect of counterpropagative signals on a graphene electrode is clearly demonstrated. These results confirm the possibility of producing all-analog components operating at several GHz for the processing of specific signals.

Jury Composition  :

Samuel MARGUERON, Maître de conférences, Université Bourgogne Franche-Comté, Directeur de thèse

Yann KERSALE, Professeur, Université Bourgogne Franche-Comté, Examinateur

Salvatore STIVALA, Associate Professor, Università degli Studi di Palermo (IT), Rapporteur

Clemens WINKEMANN, Professeur associé, Pr Grenoble INP, Néel Institute, Rapporteur

Paulo Ventura SANTOS, Directeur de recherche, Paul-Drude-Institut für Festkörperelektronik, Examinateur

Michel DEVEL, Professeur, Université Bourgogne Franche-Comté, Examinateur

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