Internal field emission at metal/diamond contact and performance of thin film field emitters: Computer simulation

Emission characteristics of metal/diamond (insulating or donor-doped) contact Geld emitters have been calculated. In the calculation, Fowler-Nordheim type electron tunneling including Schottky effect and continuity of current, when needed, are taken into account. When the diamond layer is insulating or of low donor concentration, the emission performance is not satisfactorily improved in comparison with conventional metal field emitters, because the unfavorable reduction (1/5.7) in the interfacial electric field due to the dielectric nature of diamond is adverse to the favorable effect of possible decrease in barrier height (typically from 5 to 2eV). However, when the donor density is sufficiently high, the space-charge effect in Che donor-doped diamond layer can enhance the interfacial electric field leading to a high emission current. The thickness of the diamond film in this case is preferable to be close to the space-charge Iayer width. Too much reduction of the diamond layer thickness may lose the advantage of utilizing space-charge effect of ionized donors. The possibility of diamond metal/insulator/metal (MIM) field emitters with negative work function at the face metal is also discussed in comparison with conventional MIM vacuum emitters proposed so far. (C) 1997 Elsevier Science S.A.