  Paper based thermoresistive sensors are fabricated by rubbing WS2 powder
against a piece of standard copier paper, like the way a pencil is used to
write on paper. The abrasion between the layered material and the rough paper
surface erodes the material, breaking the weak van der Waals interlayer bonds,
yielding a film of interconnected platelets. The resistance of WS2 presents a
strong temperature dependence, as expected for a semiconductor material in
which charge transport is due to thermally activated carriers. This strong
temperature dependence makes the paper supported WS2 devices extremely
sensitive to small changes in temperature. This exquisite thermal sensitivity,
and their fast response times to sudden temperature changes, is exploited
thereby demonstrating the usability of a WS2-on-paper thermal sensor in a
respiration monitoring device.
