Ultra Coherent Single Electron Emission of Carbon Nanotubes.

The single electron emitter, based on single quantized energy level, can potentially achieve ultimate temporal and spatial coherence with large emission current, which is desirable for the atomic resolution electron probe. This was first developed by constructing a nano-object on a metal tip to form a quantized double barrier structure. However, the single electron emission current can only achieve picoampere level due to the low electron tunneling rate of the heterojunction with large barrier width, which limits their practical applications. In this study, we demonstrated carbon nanotubes (CNTs) can serve as a single electron emitter with current up to 1.5 nA. The double barrier structure formed on the CNT tip enables a high tunneling rate (∼10 12 s -1 ) due to the smaller barrier width. The emitter also shows high temporal coherence (energy dispersion ∼10 meV) and spatial coherence (effective source radius ∼0.85 nm). This work represents a high coherent electron source to simplify the electron optics system of atomic resolution electron microscopy and sub-10 nm electron beam lithography. This article is protected by copyright. All rights reserved.