A study in fabrication of functionalized nanodiamond-based materials for application in high performance optoelectronic and electrochemical sensor devices

• Main Authors: Minh-Khoa BenDao, 陶明科
• Other Authors: Chii-Ruey Lin
• Language: en_US
• Online Access: http://ndltd.ncl.edu.tw/handle/84j7q5

博士 === 國立臺北科技大學 === 機電科技研究所 === 104 === Since the nanodiamonds possess the unique combinations of oustanding properties of diamond and nanostructure materials, they have been considered as promising candidate for applications in micro-machining, semiconductor, electrochemical, biomedical treatment engineering, and so forth. However, manufacturing cost, limited deposition area, and challenges in doping restricted the practical applications of nanodiamond materials. This study aims at developing process for fabricating nanodiamond materials with low cost, large deposition area, simple operation, and environment friendly. Nanodiamond particles (NDPs) were produced from commercial micron diamond powder by a novel nano-milling and purification processes. The results shown that the as-prepared NDPs are homogeneous in size of ~ 15 nm and available for further nucleation in large-area chemical vapor deposition (CVD) diamond film growth. Various surface modification methods include beads milling, hydrogenation, and thermal oxidation were developed to improve dispersion of the NDPs in aqueous solution. The as-prepared diamond suspension were found to be highly stable and have good dispersion on silicon substrate through spin-coating technique. The seeding nucleation with diamond suspension were also employed for the fabrication of NCD films using the obtained nanodiamond suspensions. Besides, other nucleation method was employed using different metal interlayers of tungsten, molybdenum, titanium, and nickel. The nanocrystalline diamond (NCD) films were synthesized using microwave plasma enhanced chemical vapour deposition (MPECVD) and possessed low surface roughness rms of ~ 8 nm and high uniformity. The fabrication of nanodiamond-based electrochemical sensor device have been developed using a novel nanodiamond composition materials consisted NDPs and carbon black powder. The results demonstrated that lead ion can be directly detected by the fabricated nanodiamond-based electrodes, opening up an avenue for future heavy metal ion sensor based on nanodiamond materials with high sensitivity, good reproducibility and stability. In other stage, the study investigated a fabrication of UV detector based on structures of NCD films and various electrode materials include gold, tungsten, molybdenum, and titanium. The one-step fabrication of metal-semiconductor-metal type using metallic interlayer as diamond nucleation and back electrodes showed high detection efficiency and fast response to UV irradiation in air ambient. The W/NCD/W structure annealed at 350 oC exhibited a good Ohmic contact characteristics and significant changes (3 orders) in photocurrent and stable repoducibility.