10:15 AM - FF05.08.01
Molybdenum Disulfides and Diselenides by Atomic Layer Deposition
Jan Macak1,2,Raul Zazpe1,2,Jaroslav Charvot1,Richard Krumpolec3,Milos Krbal1,Jan Prikryl1,Filip Bures1
University of Pardubice1,Brno University of Technology2,Masaryk University3
The success of graphene opened a door for a new class of chalcogenide materials with unique properties that can be applied in the semiconductor technology . Monolayers of two-dimensional transition metal dichalcogenides (2D TMDCs) possess a direct band gap  that is crucial for optoelectronic applications. Additionally, the direct band gap can be easily tuned by either chemical composition or external stimuli. Next to the optoelectronic applications, where a monolayer planar structure is necessary to employ, a layer of standing flakes, which possesses a large surface area, can be used for hydrogen evolution  a photodegradation of organic dyes  or as electrodes in Li ion batteries .
In principle, TMDCs can be prepared by various top-down (e.g. exfoliation) and bottom-up techniques, such as chemical vapor deposition (CVD) and atomic layer deposition (ALD) growth techniques . MoS2, a typical representative of TMDCs, has been widely studied for many applications. Recently, the possibility to employ ALD as a technique to grow MoS2 has been reported. In these works (CH3)2S2  or H2S [7, 8] were used as the S precursor and Mo(CO)6 , MoCl5  or Mo(thd)3  as the Mo precursors. From the practical point of view, MoSe2 is even more interesting than MoS2 since MoSe2 possesses a higher electrical conductivity than MoS2 [9, 10]. Recently, we have shown that ALD deposition of MoSe2  or Mo-O-Se  using ((CH3)3Si)2Se as the Se precursor and the MoCl5 or Mo(CO)6, respectively, as the Mo precursors is feasible.
The presentation will focus on the synthesis of MoS2 and MoSe2 by ALD, their characterization and applications in various fields. Experimental details and some recent photocatalytic and hydrogen evolution results will be presented and discussed.
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