Microscopic observation of catalytically etched channels and pits in MoS₂ flakes

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>With a growing interest in two-dimensional transition metal dichalcogenide (TMD), etching the structure of TMD for further application is a challenge due to its thermal stability by a high melting point. Here, we report on diverse etched structures in MoS<SUB>2</SUB> flakes based on the catalytic oxidation using a Co catalyst. After impregnated with a Co precursor, MoS<SUB>2</SUB> flakes were oxidized in air by induction heating to obtain an etched structure. As a result, microscopic observation revealed that diverse etched structures in the shape of a channel and a pit were created in the MoS<SUB>2</SUB> flakes. Especially, the catalytic etching by CoO nanoparticles produced two types of channels which have an angle of 120° and 150°, respectively. Also, a pit with a depth of approximately 3 nm was found on the oxidized surface of MoS<SUB>2</SUB> flakes. Our results open a new perspective to control the edge site of TMD flakes including S element as well as MoS<SUB>2</SUB> flakes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MoS<SUB>2</SUB> flakes are etched in the presence of cobalt oxide by catalytic oxidation. </LI> <LI> The oxidation results in etched structures like pits and channels on the flakes. </LI> <LI> Transition metal dichalcogenide including S element can be etched by this method. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>