Influence of adsorbates on the performance of a field emitter array in a high voltage triode setup

Abstract

In the present work, black-silicon field emitter arrays (FEAs) are investigated regarding the influence of residual gas pressure on the characteristics and lifetime in the high voltage triode setup. Current-voltage-characteristics at different pressure levels are recorded and show a decreasing emission current with rising pressure. This decrease can be explained by an increase of the work function and charging of the emitter surface caused by adsorbates. The emission current can be restored to its initial value by heating of the FEA up to 110 °C during active emission. With this regeneration procedure, an extended lifetime from about 20 h to 440 h at a residual gas pressure of 10−5 mbar is achieved.

The “LED‐version” of the electron gun

“…For a detailled and reproducible investigation the current needs to be controlled and constant over a longer period of time. Prommesberger et al [21] proposed a control circuit whose functionality was shown multiple times in previous lifetime measurements on silicon based FEAs [19,22]. A schematic of the transistor based regulation circuit is depicted in Fig.…”

“…The obtained spatial resolution is limited by the grain size and coating properties of the screen and high local current densities lead to local burn out and evaporation of the phosphor resulting in low lifetimes [5,31]. The evaporation of the phosphor also results in increased residual gas pressure and might therefore influence the FEA performance [22]. In addition, p-doped depletion type emitters are strongly affected by illumination [33] and therefore characterization of this types of FEAs with phosphor-screens might be challenging.…”

Quantitative Field Emission Imaging for Studying the Doping-Dependent Emission Behavior of Silicon Field Emitter Arrays

“…In the subsequent characteristics, the distributions are narrower with less prominent maximum currents. Part of this stabilization is attributable to various conditioning effects [45,46] affecting the emission of the individual tips during the initial operation. Additionally, from Figure 4d-f, it is apparent that the number of emitting tips increases significantly over the course of the measurement, due to the increasing voltage.…”

“…The presence of adsorbates away from the tip apex affects the generation of charge carriers on the surface, leading to a possible increase in the current limit of p-type FEAs [43]. Moreover, the presence of adsorbates at the tip apex can lead to a decrease in current due to a change in the work function [46]. As the constant current heats the tip during the initial minutes of CCM, the desorption rate rises.…”

Confinement Related Phenomena in MoS2 Tubular Structures Grown from Vapour Phase

“…The actual current fluctuations with constant voltage are too high for most practical applications. In previous works we presented circuits, which lead to a stabilization of the emission current (< 0.01 %) by an n-channel MOSFET [51] or by a high voltage power amplifier driven by a proportional-integral controller. [52] This method of stabilizing the emission current may also be used for these types of emitters.…”