We explored the feasibility of wafer-scale
two-dimensional (2D)
molybdenum disulfide (MoS2) layers toward futuristic environmentally
friendly electronics that adopt biodegradable substrates. Large-area
(> a few cm2) 2D MoS2 layers grown on silicon
dioxide/silicon (SiO2/Si) wafers were delaminated and integrated
onto a variety of cellulose-based substrates of various components
and shapes in a controlled manner; examples of the substrates include
planar papers, cylindrical natural rubbers, and 2,2,6,6-tetramethylpiperidine-1-oxyl-oxidized
cellulose nanofibers. The integrated 2D layers were confirmed to well
preserve their intrinsic structural and chemical integrity even on
such exotic substrates. Proof-of-concept devices employing large-area
2D MoS2 layers/cellulose substrates were demonstrated for
a variety of applications, including photodetectors, pressure sensors,
and field-effect transistors. Furthermore, we demonstrated the complete
“dissolution” of the integrated 2D MoS2 layers
in a buffer solution composed of baking soda and deionized water,
confirming their environmentally friendly transient characteristics.
Moreover, the approaches to delaminate and integrate them do not demand
any chemicals except for water, and their original substrates can
be recycled for subsequent growths, ensuring excellent chemical benignity
and process sustainability.