Thesis Committee: Gleb Finkelstein, Haiyan Gao, Stephen Teitsworth, and Seog Oh (exofficio non-voting member)
ABSTRACT:
This thesis outlines a novel approach of depositing gold nanoparticles in a controlled manner on silicon substrates. Our research seeks to improve upon the current methods of making primarily single-electron transistors and other nanodevices that use metallic nanoparticles as quantum dots. The difficulty of fabricating such working devices lies in ensuring that the nanoparticles are correctly placed and positioned in the devices. By being able to selectively deposit particles, it is possible to significantly increase the yield of functional devices.
The basic idea behind the approach is as follows. Electron-beam lithography is done on a Si substrate spin-coated with polymethyl methacrylate (PMMA) resist layer to define narrow trenches. Deposition of aminopropyltriethoxysilane (APS) followed by colloidal gold and subsequent stripping of PMMA leaves behind patterned lines of gold nanoparticles strongly attached to the substrate. Contacts can then be made to these lines to make nanodevices.
Currently, it is fairly straightforward to obtain lines that are 3 to 5 particles wide which have high densities of nanoparticles using our method. The eventual goal is to be able to consistently obtain single-file lines of gold nanoparticles (> 500nm) where the particles are in relatively close proximity to one another. We have been able to create a few of these single-file lines. However, more work needs to be done to improve the yield of such lines. Nonetheless, this method is highly promising and may prove to be easier and more efficient than current methods.
Here is the thesis in PDF: Huang_thesis.pdf