  The current integrated circuit (IC) technology based on conventional MOS-FET
(metal-oxide-semiconductor field-effect transistor) is approaching the limit of
miniaturization with increasing demand on energy. Several analog circuit
applications based on graphene FETs have been demonstrated with less components
comparing to the conventional technology. However, low on/off current ratio
caused by the semimetal nature of graphene has severely hindered its practical
applications. Here we report a graphene/MoTe2 van der Waals (vdW) vertical
transistor with V-shaped ambipolar field effect transfer characteristics to
overcome this challenge. Investigations on temperature dependence of transport
properties reveal that gate tunable asymmetric barriers of the devices are
account for the ambipolar behaviors. Furthermore, to demonstrate the analog
circuit applications of such vdW vertical transistors, we successfully realized
output polarity controllable (OPC) amplifier and frequency doubler. These
results enable vdW heterojunction based electronic devices to open up new
possibilities for wide perspective in telecommunication field.
