Abstract
Screening effect of field emission on the diamond nano-tip array with different pitches is investigated. The diamond nano-tip arrays are formed by hot-filament chemical vapor deposition (HFCVD) on aluminum oxide (AAO) template. The AAO template is fabricated by hard anodization. Compared with moderate anodization, there are many advantages for using hard anodization, such as fast growing and high regularity. The nano diamond particles are adhered onto the AAO template by Polyethylenimine pretreatment to increase the nucleation density of diamond. The diamond film is then deposited on the barrier layer of AAO template by HFCVD method. The diamond tips array is developed after removal of AAO template by wet chemical etching. The field emission effect with different nano-tip arrays are measured by field emission meter. The morphology and quality of diamond nano-tip array are examined by scanning electron microscopy (SEM) and Raman spectroscopy, respectively. The innovative triangular pyramidal structures are obtained successfully with tip radius of about 15 nm-30 nm, and height of 100 nm-200 nm at different pitches from 50 nm to 300 nm. As a result, the lowest turn-on voltage of 5.4 V/μm and highest field emission current density of 8.4 μA/cm2 can be obtained at the smallest pitch- height ratio of 0.25-1 without screening effect in the current study.