ISMO

Institut des Sciences Moléculaires d'Orsay


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Home > Research Teams > Surfaces, Interfaces, Molecules & 2D Materials (SIM2D) > Surface chemistry & slow electrons, 0-50eV

Surface chemistry & slow electrons, 0-50eV

Introduction

(french version)
The researches performed by this team primarily involve the study of the interaction of low energy electrons (0-25 eV) with condensed molecular systems and with deposited molecules on substrates. The interaction between low-energy electrons and molecules may lead to several processes especially to those that are dissociative in nature. These processes can be exploited to carry out chemical modification of surfaces and creation of new interfaces. This team therefore aims to understand, in a fundamental level, the processes and mechanisms involved in these interactions.

Understanding electron-induced processes can be useful for a variety of applications. Certain techniques which utilize high energy radiation to irradiate surfaces produce low-energy secondary electrons that cause changes in the physical and chemical properties of the irradiated surface. These techniques are used in an array of chemical and biological applications from radiotherapy, to the development of biochemical sensors, to fabrication of circuits by nanolithography and even in astrochemistry. Knowledge on low-energy electron interactions on surfaces involved in these techniques could help device efficient means to control and optimize these processes.

Our team is under the SIREN group of ISMO and is led by experts in the field of surface science and electron-molecule interactions:

- Anne Lafosse, Professor and Research Director
- Lionel Amiaud, Maître de Conférences
- Céline Dablemont, Maître de Conférences
- Leo Albert Sala, Doctoral Researcher


Last publications

2018

- Strain relaxation and epitaxial relationship of perylene overlayer on Ag(110)
N. Kalashnyk, L. Amiaud, C. Dablemont, A. Lafosse, K. Bobrov, L. Guillemot
J. Chem. Phys., 148, p. 214702

- Response under low energy irradiation of a thin film of a potential copper precursor for Focused Electron Beam Induced Deposition (FEBID)
L. Sala, I. B. Szymańska, C. Dablemont, A. Lafosse, L. Amiaud
Beilstein J. Nanotechnol., 9, p. 57-65

2017

- Interfacial water on organic substrates at cryogenic temperatures: hydrogen bonding and quantification in the submonolayer regime
D. Houdoux, J. Houplin, L. Amiaud, A. Lafosse, C. Dablemont
Phys. Chem. Chem. Phys., 19, p. 2304-2312

2015

- Electron processing at 50 eV of terphenylthiol Self-Assembled Monolayers: contributions of primary and secondary electrons
J. Houplin, C. Dablemont, L. Sala, A. Lafosse, L. Amiaud
Langmuir, 31, p. 13528-13534

- DOS and electron attachment effects in the electron-induced vibrational excitation of terphenylthiol SAMs
J. Houplin, L. Amiaud, C. Dablemont, A. Lafosse
Phys. Chem. Chem. Phys., 17, p. 30721-30728

- A combined DFT/HREELS study of the vibrational modes of terphenylthiol SAMs
J. Houplin, L. Amiaud, T. Sedzik, C. Dablemont, D. Teillet-Billy, N. Rougeau, A. Lafosse
Eur. Phys. J. D, 69, p. 217


Research Partners and Collaborations



Other research partners and european networks


Studies on low-energy electron interaction with the following systems have been performed in our laboratory:

- Molecular Ices

Previous studies by the group dealt with fundamental studies on processes induced by the impact of low-energy electrons on molecular ices especially in the context of interstellar media.


- Self-Assembled Monolayers (SAMs)

Low-energy electron irradiation to modify SAM surfaces can be an efficient tool in the development of functionalized surfaces for biochemical sensing.


Laboratory Techniques and Equipment

Our laboratory is equipped with the High Resolution Electron Energy Loss Spectrometer (HREELS) housed in an ultra-high vacuum set-up that is also installed with an electron gun, a Quadrupole Mass Spectrometer (QMS), and a closed-cycle helium cryostat. The QMS is useful for Temperature Programmed Desorption (TPD) and Electron Stimulated Desorption (ESD) experiments which, together with the HREELS, provide a wealthy combination of complementary techniques for the characterization of low-energy electron-irradiated adsorbed molecules on surfaces.

High Resolution Electron Energy Loss Spectroscopy (HREELS), a surface-sensitive technique, allows for the characterization of a sample surface on the basis of the energy loss undergone by electrons colliding with the sample surface. The energy loss spectrum obtained from this technique is related to vibrational excitations of the surface molecules being probed. Composition and orientation of molecules on the surface can be deduced from the energy loss spectra generated from this technique. Excitation functions may also be obtained using this spectrometer by observing specific energy losses as a function of incident electron energy. From these excitation functions, information regarding excitation mechanisms and density of electronic states of substrates can be obtained.

Low-Energy Electron Irradiation utilizes an electron gun capable of producing low-energy electrons that can be exposed directly to the sample. The energy of the electrons released can be adjusted to study modifications on the surface at various electron energies.

The Quadrupole Mass Spectrometer (QMS) housed in the UHV is optimized for the low pressure detection of neutral species. This device can detect fragments desorbing from the surface during electron irradiation.

The Closed-Cycle Helium Cryostat attached to the sample holder can control sample surface temperatures from 20 to 800 K.

The following techniques are also widely used by the group from the combination of tools mentioned above:

Electron Stimulated Desorption (ESD) combines the use of the electron gun and the QMS. In this technique, desorbed fragments are detected during electron-irradiation of the sample. The desorbed fragments are released in gas phase and can be quantified using the QMS.

Irradiation can also be done at lower temperatures with the help of the cryostat to trap desorbed fragments by physisorption. The adsorbed fragments on the surface can then be observed through HREELS. Studying these fragments can elucidate the nature and mechanism of observed electron-induced processes.

Temperature Programmed Desorption (TPD) is a technique in which desorbed species are detected when the sample temperature is increased at a constant rate. It combines the use of the cryostat for temperature control and the QMS for the detection of desorbed species. The desorbed molecules are successively released after overcoming their distinct adsorption energies by the accompanying increase in temperature. Multilayer and monolayer desorptions can be tracked using this technique as well as thermally-induced formation of new species.


Low-energy electron irradiation of self-assembled monolayers (SAMs)

Low-energy electron irradiation to modify SAM surfaces can be an efficient tool in the development of functionalized surfaces for biochemical sensing.

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Research Partners and Collaborations

Presented here is a list of our chief partners and collaboration.

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Electron-induced processes on mixed molecular ices

Previous studies by the group dealt with fundamental studies on processes induced by the impact of low-energy electrons on molecular ices especially in the context of interstellar media.

Read more

Electron interaction with condensed and adsorbed molecular systems

A brief presentation of the research topics, interests, and competencies of the group.

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