Fabrication And Supercapacitive Properties Of Micro-Nano Structures Based On C-MEMS

Carbon microstructures can be fabricated using photoresist as precursor bycombining photolighography process and pyrolysis at high temperature on conventionalcarbon microelectromechanical systems （C-MEMS）. This glass carbon have excellentelectronic and heat conductivity, better biocompatible properties and chemical inertia.MEMS has hold great research interests, and could have been applied in many fields suchas biology, medicine and energy. Hence, the micro power for micro systems has been ingreat demanding. As an important energy devices, supercapacitor can have both highpower density and high energy density. The supercapacitors with carbon as the electrodehave been a great research interest. Based on all above, C-MEMS could be applied todevelop new methods of fabricating micro-nano structures, and further to investigate thesupercapacitive properties. On this study, SU-8was chosed as the precursor on theC-MEMS process. The contents of this thesis are as follows:Fabrication of suspended C-MEMS has been achieved with the diffraction effect, andparameters have been optimized for controllable fabrication. With the supercapacitive teston suspended C-MEMS, the specific capacitance could be increased to3.8times. Withgraphite deposition on the SU-8structures before pyrolysis, C-MEMS with wrinklesurfaces have been achieved. The specific capacitance could be increased to7.5times.With a Cu thin layer deposited on the SU-8structures, C-MEMS/SiO₂micro-nanostructures have been realized, and a carbonization-assisted copper-catalyzed mechanismhas been proposed. Moreover, more process details have been investigated to fabricateC-MEMS/SiO₂with diverse morphologies. Typical C-MEMS/SiO₂has been applied onthe supercapacitive test, and the specific capacitance could be increased to about13times.Manganese dioxide （MnO2） has been integrated to C-MEMS through electrochemicaldeposition method. By controlling deposition time, C-MEMS/MnO2could be synthesizedwith different morphologies. Exellent supercapacitive properties have been shown on theC-MEMS/MnO2, while the specific capacitance could be increased to as high as30times.