While experimentalists have succeeded in fabricating nanoscale field electron emitters in a variety geometries and materials for use as electron sources in vacuum nanoelectronic devices, theory and modeling of field electron emission has not kept pace. Treatments of field emission which address individual deviations of real emitter properties from the conventional Fowler-Nordheim (FN) theory, such as emission from semiconductors, highly-curved surfaces, or low-dimensional systems, have been developed, but none have sought to treat these properties coherently within a single framework. As a result, this work presents a multidimensional, semiclassical framework for field emission, from which models for field emitters of any dimensionality, geometry, and material can be derived; the model is then utilized it to derive models for: i) a highly-curved, nanoscale, metal emitter tip; ii) a bulk silicon emitter with a surface quantum well and finite electron supply; and iii) a cylindrical silicon nanowire emitter. Findings show that the dimensionality, geometry, and material of field emitters all play a critical role in field emission processes at the nanoscale. Accordingly, emitter-specific models beyond FN theory must be employed for a realistic theoretical treatment of modern field emitters and the semiclassical framework for field emission serves as a versatile foundation upon which such models can be built.
Thesis Supervisor: Prof. Tayo Akinwande