Electron field emission from cluster-assembled carbon thin films

– Cluster-assembled carbon films deposited at room temperature from a supersonic cluster beam are found to be good electron field emitters. The films have been characterized by Raman spectroscopy showing a largely sp bonded character. Scanning Electron Microscopy shows that the films have a low-density granular structure, characterized by voids on the nanoscale. We have observed a threshold field of 0.75 V/μm for an emission current density of 1 μA/cm, among the lowest values reported for a carbon phase. The observed field emission characteristics suggest that this nanostructured material may be interesting for flat panel display applications. The realization of high-performance vacuum microelectronic devices and flat panel displays requires cold cathode emitters providing intense and stable electron beams. Electron field emission (FE), on which cold cathode are based, consists of the injection of electrons from a solid into vacuum through a potential barrier at its surface. By applying an accelerating electric field, this barrier can be decreased in height and width, enhancing the electron emission. To achieve FE at macroscopic electric fields reasonably low for practical applications, arrays of sharp tips of Mo or Si are used [1]. Since reliable fabrication of microtip arrays over large area is difficult, films of materials with low electron affinity have been proposed as a viable solution for the production of FE displays [1]. Field emission occurs relatively easily from various carbon-based films, such as diamond [2, 3], nanocrystalline diamond [4-6], diamond-like carbon [7], and hydrocarbon polymers [8]. It () E-mail: [email protected]