  The recent discovery of magic angle twisted bilayer graphene (MATBG), in
which two sheets of monolayer graphene are precisely stacked to a specific
angle, has opened up a plethora of new opportunities in the field of topology,
superconductivity, and other strongly correlated effects. Most conventional
ways of preparing twisted bilayer devices require the use of high process
temperatures and solvents and are not well-suited for preparing samples which
need to be flipped to be compatible with characterization techniques like STM,
ARPES, PFM, SThM etc. Here, we demonstrate a very simple polymer-based method
using Polyvinyl Chloride (PVC), which can be used for making flipped twisted
bilayer graphene devices. This allowed us to produce flipped twisted samples
without the need of any solvents and with high quality as confirmed by
Piezoresponse Force Microscopy. We believe that this dry flip technique can be
readily extended to twist 2D materials beyond graphene, especially
air-sensitive materials which require operation under inert atmosphere, where
often solvents cannot be used.
