Fig. 5
From: Active bialkali photocathodes on free-standing graphene substrates
a Unit cell of graphene on K2CsSb, with C, Cs, K, Sb atoms shown as black, blue, red and yellow, respectively. Views are shown along [111] direction (left) and (111) planes (right). b The local electrostatic potential without (left) and with (right) graphene on the surface of K2CsSb. All curves are averaged over the directions transverse to the surface normal. The red curve shows a suitable macroscopic average over approximately 5 Å to demonstrate the energy zero level, relative to vacuum. Inset is enlarged. c Direction of dipole at graphene-K2CsSb interface. Blue and red regions indicate electrons are being lost and gained, respectively. Specifically, electrons are being lost from the Cs atoms (regions indicated by black circular lines), and are gained by the C atoms (red honeycomb regions). d Band diagram at graphene-K2CsSb interface with inputs from b and c
