  We demonstrate multiplexed terahertz emitters that exhibits 2 THz bandwidth
that do not require an external bias. The emitters operate under uniform
illumination eliminating the need for a micro-lens array and are fabricated
with periodic Au and Pb structures on GaAs. Terahertz emission originates from
the lateral photo-Dember effect and from the different Schottky barrier heights
of the chosen metal pair. We characterize the emitters and determine that most
terahertz emission at 300 K is due to band-bending due to the Schottky barrier
of the metal.
