  Determining the electronic properties of nanoscopic, low-dimensional
materials free of external influences is key to discovery and understanding of
new physical phenomena. An example is the suspension of graphene, which has
allowed access to their intrinsic charge transport properties. Furthermore,
suspending thin films enables their application as membranes, sensors, or
resonators, as has been explored extensively. While the suspension of
covalently-bound, electronically-active thin films is well established,
semiconducting thin films composed of functional molecules only held together
by van-der-Waals interactions could only be studied supported by a substrate.
In the present work, it is shown that by utilizing a surface-crystallization
method, electron conductive films with thicknesses of down to 6nm and planar
chiral optical activity can be freely suspended across several hundreds of nm.
The suspended membranes exhibit a Young's modulus of 2 to 13 GPa and are
electronically decoupled from the environment, as established by temperature
dependent field-effect transistor measurements.
