Low Temperature Direct of Graphene onto Metal Nano‐Spindt Tip with Applications in Electron Emission

Graphene has been known for its superior electronic properties ever since its discovery in 2004. The high aspect ratio and ballistic transport properties exhibited by this one‐dimensional material are especially useful for electron emission applications. However, they are typically grown horizontally and excess efforts, such as the use of transfer techniques, is required to orientate them before effective electron emission from the graphene edges can occur. These transfer techniques have been shown to lead to additional defects to the as‐grown graphene structure, thereby degrading its properties. Here, we present an approach to directly fabricate graphene onto metal nano‐sized spindt tips (or nanocones) using the solid‐state transformation of carbon deposited from a pulsed laser system at low temperature. Besides providing a layer of chemical and mechanical protection for the metal nanocones, the graphene‐on‐metal nanocones gave enhanced emission properties compared to bare metal nanocones. This was due to the reduction of effective field emission tunneling barrier, which was a result of graphene‐metal charge transfer interactions. Controlling the metal nanocones density was also an important factor in determining the field emission performance, as electron screening from neighboring cones should be minimized.