Abstract
In this study, we found that Mo-coating on Si-substrate can significantly improve the formation of diamond nuclei and the growth behavior of ultra- nanocrystalline diamond (UNCD)films. Contrary to the phenomenon that diamond nuclei are only scarcely formed on bare Si-substrates, this work can growth high quality UNCD films on the Mo-coated Si- substrates. While the Mo-coating markedly enhances the nucleation of diamonds, it degrades the electron field emission (EFE) properties of UNCD films. It is attributed to the conversion of the conducting Mo- metallic film into a resistive Mo2C layer during growth of UNCD films. A sufficiently thick Mo-layer is found to enhance the nucleation of diamonds, while minimizing deleterious effect on their EFE properties with an improved turn-on-field of 13 V/□m and a current density of 55 mA/cm2 at the applied field of 30 V/□m. Moreover, we try to fabricate a SAW device using UNCD films incorporated with AlN piezoelectric films. Because AlN films peel off easily on UNCD films, the coated Al films are acted as buffer layer for AlN growth. The electrode of SAW devices was fabricating using the nano-transfer printing process.