  On-chip temperature sensing on a micro- to nanometer scale is becoming more
desirable as the complexity of nanodevices and size requirements increase and
with it the challenges in thermal probing and management. This highlights the
need for scalable and reliable temperature sensors which have the potential to
be incorporated into current and future device structures. Here, we show that
U-shaped graphene stripes consisting of one wide and one narrow leg form a
single material thermocouple that can function as a self-powering temperature
sensor. We find that the graphene thermocouples increase in sensitivity with a
decrease in leg width, due to a change in the Seebeck coefficient, which is in
agreement with our previous findings and report a maximum sensitivity of
$\Delta S \approx$ 39 $\mathrm{\mu}$V/K.
