  Paper holds the promise to replace silicon substrates in applications like
internet of things or disposable electronics that require ultra-low-cost
electronic components and an environmentally friendly electronic waste
management. In the last years, spurred by the abovementioned properties of
paper as a substrate and the exceptional electronic, mechanical and optical
properties of van der Waals (vdW) materials, many research groups have worked
towards the integration of vdW materials-based devices on paper. Recently, a
method to deposit a continuous film of densely packed interconnects of vdW
materials on paper by simply rubbing the vdW crystals against the rough surface
of paper has been presented. This method utilizes the weak interlayer vdW
interactions and allows cleaving of the crystals into micro platelets through
the abrasion against the paper. Here, we aim to illustrate the general
character and the potential of this technique by fabricating films of 39
different vdW materials (including superconductors, semi-metals,
semiconductors, and insulators) on standard copier paper. We have thoroughly
characterized their optical properties showing their high optical quality: one
can easily resolve the absorption band edge of semiconducting vdW materials and
even the excitonic features present in some vdW materials with high exciton
binding energy. We also measured the electrical resistivity for several vdW
materials films on paper finding exceptionally low values, which are in some
cases, orders of magnitude lower than those reported for analogous films
produced by inkjet printing. We finally demonstrate the fabrication of
field-effect devices with vdW materials on paper using the paper substrate as
an ionic gate.
