A field emitter structure, comprising: a base substrate (42); a field emitter element (48) on the base substrate; a multilayer differentially etched dielectric stack (58, 60) circumscribingly surrounding the field emitter element on the base substrate; and a gate electrode (66) overlying the multilayer differentially etched dielectric stack, and in circumscribing spaced relationship to the field emitter element. Also disclosed are electron source devices, comprising an electron emitter element including a material selected from the group consisting of leaky dielectric materials, and leaky insulator materials, as well as electron source devices, comprising an electron emitter element including an insulator material doped with a tunneling electron emission enhancingly effective amount of a dopant species, and thin film triode devices.