Alternative Definition of the Apex Field Enhancement Factor for a Regular Array of Electrostatically Interacting Post Emitters

In cold field electron emission (FE), the so-called “applied electrostatic field” is an important parameter used to model an ideal FE device. Normally it is used to define the local field enhancement factor (FEF), arguably the most analyzed parameter used to assess the performance of an emitter. However, a consistent definition of the applied field is not straightforward when emitters are close to the counter-electrode, since the local field distribution is then not uniform in the FE device, due to electrostatic interactions between emitters and with the counter-electrode. In this work, we report consistent new definitions of the applied electrostatic field (and of the related FEF), suitable for the “close-proximity” situation. These new definitions are based on an “effective distance of field penetration” measured from the counter-electrode. Advantages and disadvantages of these new definitions are pointed out.