▎ 摘　　要

Field-desorption and field-emission electron microscopy methods have been used to study the effect of a strong electric field on the processes of potassium and cesium desorption from the graphene surface on an iridium field emitter. It was found that two phases of field desorption may exist for these alkali metals. In the low-field phase, alkali metal atoms adsorbed on the surface are desorbed. The existence of the high-field phase is attributed to the egress from under the graphene film and ionization of intercalated alkali metal atoms under the action of the electric field.