title: Investigations on diamond nanostructuring of different morphologies by the reactive-ion etching process and their potential applications.
abstract: We report the systematic studies on the fabrication of aligned, uniform, and highly dense diamond nanostructures from diamond films of various granular structures. Self-assembled Au nanodots are used as a mask in the self-biased reactive-ion etching (RIE) process, using an O2/CF4 process plasma. The morphology of diamond nanostructures is a close function of the initial phase composition of diamond. Cone-shaped and tip-shaped diamond nanostructures result for microcrystalline diamond (MCD) and nanocrystalline diamond (NCD) films, whereas pillarlike and grasslike diamond nanostructures are obtained for Ar-plasma-based and N2-plasma-based ultrananocrystalline diamond (UNCD) films, respectively. While the nitrogen-incorporated UNCD (N-UNCD) nanograss shows the most-superior electron-field-emission properties, the NCD nanotips exhibit the best photoluminescence properties, viz, different applications need different morphology of diamond nanostructures to optimize the respective characteristics. The optimum diamond nanostructure can be achieved by proper choice of granular structure of the initial diamond film. The etching mechanism is explained by in situ observation of optical emission spectrum of RIE plasma. The preferential etching of sp(2)-bonded carbon contained in the diamond films is the prime factor, which forms the unique diamond nanostructures from each type of diamond films. However, the excited oxygen atoms (O*) are the main etching species of diamond film.
authors.affiliation: Department of Engineering and System Science, National Tsing Hua University, Hsinchu 300, Taiwan, Republic of China.
authors.forename: Srinivasu
authors.initials: S
authors.lastname: Kunuku
authors.forename: Kamatchi Jothiramalingam
authors.initials: KJ
authors.lastname: Sankaran
authors.forename: Cheng-Yen
authors.initials: CY
authors.lastname: Tsai
authors.forename: Wen-Hao
authors.initials: WH
authors.lastname: Chang
authors.forename: Nyan-Hwa
authors.initials: NH
authors.lastname: Tai
authors.forename: Keh-Chyang
authors.initials: KC
authors.lastname: Leou
authors.forename: I-Nan
authors.initials: IN
authors.lastname: Lin
mesh_terms: D016880:Anisotropy; D015374:Biosensing Techniques; D002244:Carbon / Q000737:chemistry; D003460:Crystallization; D018130:Diamond / Q000737:chemistry*; D007477:Ions; D049449:Luminescence; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D009584:Nitrogen / Q000737:chemistry; D055095:Optics and Photonics; D010100:Oxygen / Q000737:chemistry; D010777:Photochemistry / Q000379:methods; D013053:Spectrophotometry / Q000379:methods; D013499:Surface Properties; D013696:Temperature
chemical_list: D007477:Ions; D002244:Carbon; D018130:Diamond; D009584:Nitrogen; D010100:Oxygen