posted on 2021-12-01, 19:33authored bySuichu Huang, Jingang Li, Jie Fang, Hongru Ding, Wentao Huang, Xuezeng Zhao, Yuebing Zheng
Two-dimensional monolayer and few-layer
transition-metal dichalcogenides
(TMDs) are promising for advanced electronic and photonic applications
due to their extraordinary optoelectronic and mechanical properties.
However, it has remained challenging to produce high-quality TMD thin
films with controlled thickness and desired micropatterns, which are
essential for their practical implementation in functional devices.
In this work, a self-limiting opto-electrochemical thinning (sOET)
technique is developed for on-demand thinning and patterning of TMD
flakes at high efficiency. Benefiting from optically enhanced electrochemical
reactions, sOET features a low operational optical power density of
down to 70 μW μm–2 to avoid photodamage
and thermal damage to the thinned TMD flakes. Through selective optical
excitation with different laser wavelengths based on the thickness-dependent
band gaps of TMD materials, sOET enables precise control over the
final thickness of TMD flakes. With the capability of thickness control
and site-specific patterning, our sOET offers an effective route to
fabricating high-quality TMD materials for a broad range of applications
in nanoelectronics, nanomechanics, and nanophotonics.