Nano-tip emission of tetrahedral amorphous carbon

Abstract

Various forms of tetrahedral amorphous carbon were deposited on n-type silicon (100) substrate. Tetrahedral amorphous carbon is an excellent electron emitter for field emission array (FEA) applications. The negative electron affinity (NEA) of diamond surface was believed to facilitate the electron emission for diamond-like carbon. However, in this research, we have demonstrated that the geometric enhancement factor may be even more effective to promote electron emission. Moreover, we have succeeded in depositing high-density (4×10 10 emitters/cm 2) of nano-sized emitters. The electrons are emitted under both the effect of enhanced field due to the sharp tips, and the optimized distortion of tetrahedral bonding of carbon atoms. The sp 3/(sp 3+sp 2) ratio of C–C bonded tetrahedral amorphous carbon films was measured by ESCA and Raman; and the geometry of emitters by AFM. The lowest turn on applied field strength of 4.6 V/μm was found at the current density of 10 μA/cm 2. High reproducibility of field emission was also observed in this study.