/MX2 cleaning by combination liquid solvent and plasma ashing

MX2 cleaning by combination liquid solvent and plasma ashing

Leuven | More than two weeks ago

You will study how to better clean 2D materials (MoS2, WS2) by combining solvent(s) and plasma exposure.

Monolayer MX2 (transition metal dichalcogenides) are considered as alternative channel materials for advanced CMOS devices. The construction of CMOS transistors requires to clean the MX2 film multiple times, using various (wet) chemicals. It has been observed recently that the contact of the 2D layer with solvent is inducing major changes in their optical response (photoluminescence, Raman peaks) but also in their transport properties (Ion/Ioff, mobility, etc...). The interplay between dry cleaning (using remote plasma clean for instance) and wet cleans has also been highlighted as a source of MX2 modification, which need to be better understood and controlled.


In this internship, we will study the impact of various post-processing treatments on the synthetic, MOCVD grown WS2 monolayers. Various solvents and/or diluted chemistries will be used to treat the WS2 films, varying concentration, additives, temperature, dip time and surface pre-treatments (H2 plasma, UV-O3). The quality of the WS2 monolayers will be studied by means of photoluminescence, AFM, XPS, WCA. Transport properties will be tentatively studied using ion gel gating. The long-term objective is to establish a link between the physico-chemical properties of the solvents and the changes induced on the WS2 films. The short-term objective is to determine which solvents or diluted acid/base are damaging the WS2 films.

Type of project: Internship, Thesis

Duration: 4 to 8 months

Required degree: Master of Science, Master of Engineering Technology, Master of Engineering Science

Required background: Chemistry/Chemical Engineering, Physics, Materials Engineering

Supervising scientist(s): For further information or for application, please contact: Jean-Francois de Marneffe (Jean-Francois.deMarneffe@imec.be)

Imec allowance will be provided for students studying at a non-Belgian university.

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