Photoemission Assisted by Low workfunction Nanoparticle Waveguide Integrated Device

Photoemission has been spotlighted due to its wide usages in free electron laser source and vacuum electronic high-power devices. Photon assisted electron emitter is typically limited by i) low quantum efficiency and ii) high work function of the emitter. Here, we demonstrate a hybrid photoemitter using a lanthanum hexaboride (LaB
6
) nanoparticle on single layer graphene assisted by waveguide structure to pass through these challenges. LaB6 nanoparticle, which has low work function (2.69eV) is an ideal material for electron emission purposes due to its miniature dimensions, as well as excellent electrical, thermal, and mechanical properties. By integrating LaB
6
on top of graphene with waveguide we could evanescent coupling occurs through longer interaction length and photons can be absorbed efficiently compared to free space laser illumination. In addition, nanoparticles with the average diameter of 4 nm are at the order of electron mean free path and electron emission occurs with fewer scattering compared to electron emission from bulky metallic emitters. Hybrid photoemitter can open a new pathway towards realizing high power devices for commercial usage.