Transition of field emission to space-charge-limited emission in a nanogap

This letter presents a quantum model showing the transition of electron field emission at low current to space-charge-limited emission at high current in a nanogap. It is found that the classical transition models are no longer valid when the electron de Broglie wavelength is comparable to the gap spacing. The transition from the Fowler-Nordheim law at low current to the quantum Child-Langmuir law at high current in a nanogap is calculated for various conditions. (c) 2006 American Institute of Physics.