Non-linear field emission characteristics of copper oxide nanorod mesh: Geometrical interpretation of a structurally heterogeneous emitter

A variety of structurally heterogeneous nanostructured systems are known to exhibit nonlinear field emission characteristics (Fowler-Nordheim Plot). This behavior has earlier been ascribed to various reasons such as the emitter morphology or the state of aggregation of the individual components constituting the nanostructure. Here, we consider a random mesh of Cu2O nanorods as a model system, and investigate – both experimentally and analytically – the field emission from the sidewalls of this multi-layered nano-mesh. We show that the strongly non-linear emission characteristics (that is observed experimentally) can be simply and accurately simulated by summing over the emission from the successive layers of a model, multi-layer structure. The successive monolayers are shown to “turn on” at different values of applied voltage, naturally leading to a field-dependent enhancement factor.