1Synthesis of Carbon Nanoflakes by Radio-Frequency Sputtering and Their Field Emission Characteristics

The growth, structure and field emission properties of the two-dimensional carbon nanoflakes (CNFs) produced by radio-frequency (RF) sputtering without any catalyst or special substrate treatment have been investigated. The effects of deposition parameters (such as deposition time, sputtering gas composition, substrate temperature and RF power) on the structure and properties of the CNFs were also studied. Possible growth mechanism of the CNFs has been discussed with time evolution of surface microstructure. These films contain nanosized diamonds and allotropic phases (i-carbons and graphites) embedded in amorphous carbon films. The electron field emission (EFE) process can be turned on at E0=2.8 V/m, achieving an EFE current density of Je = 1 mA/cm2 at a 5 V/m applied field. The low turn-on field of 2.8 V/µm for electron field emission suggests that the CNFs could be used as a potential edge emitter. Since the electron field emission (EFE) display was first demonstrated by Spindt et al.,1) the development of field emission materials became a key issue in vacuum microelectronics utilizing EFE emitters. Generally, an increase in emission current density and a decrease in the turn-on field can be achieved by either fabricating a sharp edge or tip as the emission source2) or employing a lo