Field emission mechanism insights of graphene decorated with ZnO nanoparticles

Abstract

Graphene decorated with ZnO nanoparticles (G–ZnO hybrids) were prepared on n-Si substrates. The microstructures and chemical states of these hybrids were analyzed. Based on these experimental results, a field emission enhanced mechanism of the G–ZnO hybrids related to stable oxygen groups in the form of cyclic edge ethers is proposed. G–ZnO hybrids consist of a higher ratio of C–O–C chains than in graphene structures. This causes the potential barrier the electrons have to overcome in vacuum to be further diminished, resulting in a lower work function. Consequently, both the potential barrier height and width for the electrons emission are further reduced. So electrons can easily tunnel through the full barrier width, causing a larger field emission current in the G–ZnO hybrids. Such insight into the C–O–C chains from the G–ZnO hybrids offers the prospect for understanding the physical mechanism and future novel applications as field emitters.