Abstract
Abstract In this thesis, one-dimensional Si nano-materials with different morphologies were prepared by electroless metal deposition (EMD) process on different oriented Si wafers. Ultra-nanocrystallined diamond (UNCD) films were deposited on these one-dimensional Si nanowire (SiNW) array templates by microwave plasma enhanced chemical vapor deposition (MPECVD) method as field emission devices. Electroless metal deposition (EMD) process was used to prepare large area SiNWs array with different wire diameters and densities on patterned Si wafers; dendrite SiNW arrays could also be prepared. Field emission properties of these SiNW arrays are strongly correlated with the wire diameters and densities of SiNW arrays. Turn-on field (E0) decreased from 8.8 V/□m to 7.6 V/ □m as the diameter of SiNW arrays decrease; dendrite SiNW arrays could further decrease the turn-on field to 2.0 V/□m. The relationships between field emission properties and growth mechanism of different morphologies SiNW arrays are discussed. In order to further improve the field emission properties, UNCD films were deposited on these SiNW array templates by MPECVD method with different pre-nucleation techniques. The field emission properties of these one-dimensional nano-materials are improved significantly by covering UNCD on surface, the turn-on field decreased from 7.6 V/□m to 3.8 V/□m. The effects of different pre-nucleation technique on field emission properties of UNCD covered SiNW arrays are also discussed.