Doping of solution-processed two-dimensional transition metal dichalcogenides
Visualitza/Obre
Estadístiques de LA Referencia / Recolecta
Inclou dades d'ús des de 2022
Cita com:
hdl:2117/362488
Correu electrònic de l'autorestevemarcoutlook.com
Realitzat a/ambÉcole polytechnique fédérale de Lausanne
Tipus de documentProjecte Final de Màster Oficial
Data2021-10-31
Condicions d'accésAccés obert
Llevat que s'hi indiqui el contrari, els
continguts d'aquesta obra estan subjectes a la llicència de Creative Commons
:
Reconeixement-NoComercial-SenseObraDerivada 3.0 Espanya
Abstract
Semiconducting transition metal dichalcogenides (TMDs) such as MoS2, WSe2 or WS2 have attracted a lot of interest in
recent years because of their outstanding optoelectronic properties including tunable bandgap or strong light absorption in the visible range, even at sub-micrometer thickness. Furthermore, doping these materials with transition metal
atoms is an approach which can additionally modify a TMDs’ optoelectronic properties and therefore could enable these
TMDs to take part in new applications.
Indeed, one method to exfoliate TMD materials is the electrochemical intercalation of TMDs with THA+ molecules. Recently this method was altered to make it more scalable, using annealed pellets made from commercially available
powder. This method is readily adaptable such that bulk TMDs are doped in the annealing phase before being exfoliated
into doped 2D TMD nanoflakes.
In this work we present an extensive study regarding p-type doping of MoS2 with Niobium (Nb) for different atomic
concentrations. We confirm the incorporation of the dopant agent to the TMD crystal lattice and observe consequential
changes in the optoelectronic properties of the resulting nanoflakes. Besides, from 0.75% Nb doping the intrinsic n-type
MoS2 displays ambipolar due to the p-type behavior added by Nb atoms. Consequently, NbMoS2 shows promise as a
building block of ultra-thin ambipolar field effect transistors (FETs).
We follow up with the incorporation of n-type dopant agent Rhenium (Re) as preliminary story. Here, Re is also confirmed to enter at MoS2 crystal structure. However, as it stands 0.5% and 1% Re doping to MoS2 are not beneficial for
PEC performance of this material.
Finally, we show that this method can also be used for other TMDs such as p-type WSe2 and n-type WS2, showcasing
the universality of this method. Here, dopant agent incorporation to the TMDs crystal lattices is also confirmed and
therefore optoelectronic properties of WSe2 and WS2 are also demonstrated to change because of Nb addition.
In summary, we successfully dope 2D TMD materials using a scalable, solution-processable method and we show that
these doped materials have potential in future ultrathin optoelectronic devices.
TitulacióMÀSTER UNIVERSITARI EN ENGINYERIA QUÍMICA (Pla 2019)
Col·leccions
Fitxers | Descripció | Mida | Format | Visualitza |
---|---|---|---|---|
Thesis_MarcEsteve.pdf | 2,698Mb | Visualitza/Obre |