Theory of Thermionic Electron Emission for 2D Materials

Abstract

This chapter provides a brief overview on the recent development of the thermionic electron emission models for two-dimensional (2D) materials, such as graphene. It describes that the traditional models developed decades ago, like Richardson–Dushman law for thermionic emission and Fowler–Nordheim law for field emission, are no longer valid due to the unique physical properties of 2D materials. The chapter highlights the different temperature scaling laws for thermionic emission from 2D materials at different conditions such as lateral or vertical emission and electron momentum conservation. It introduces a recently developed universal thermionic emission model for 2D electronic systems which offers a unifying theoretical framework to understand the thermionic emission physics in 2D materials. The chapter focuses on the new developments of electron thermionic emission theory for 2D atomically thin nanomaterials, such as graphene, which has attracted tremendous research attentions in recent years.