  The exponentially growing number of interconnected devices in the Internet of
Things poses an increasing amount of challenges to the field of cyber security
and encryption. For authenticated use and communication, each device must
securely store and apply secret keys without giving a potential attacker the
possibility to access them neither by software nor hardware attacks. In 2002,
the concept of Physical Unclonable Function emerged to counteract the inherent
threats, associated with this trend. Physical disordered systems are excited by
external stimuli and can thereby be uniquely identified. 2D materials have
profoundly different characteristics when isolated from their bulk form to few-
or monolayers. Transition metal dichalcogenides represent a potential PUF
candidate since, unlike graphene, they feature a bandgap and are thus
semiconducting. Furthermore, a random percolation network can be formed from
them, which is expected to possess an electrical response that is uniquely
identifiable yet unpredictable. This work has built the foundation for
implementing a PUF consisting of a TMD, namely tungsten disulfide. The material
has been synthesized using chemical vapor deposition in the close proximity
approach. In order to fabricate a large-scale inter-connected surface
consisting of WS2, the growth parameters are selected and enclosed by a
preliminary trial and error optimization and ultimately optimized by Design of
Experiments. This yields a potentially available PUF area of several
millimeters, which was then patterned and contacted with initial trials.
