Date of Award
Doctor of Philosophy in Electrical Engineering - (Ph.D.)
Electrical and Computer Engineering
Karl D. Moeller
Gerald Martin Whitman
Graphene - monolayer or a few layers of graphite -- has proven to possess remarkable properties: large thermal conductivity, mechanical robustness, two-dimensional ultra large electronic mobility, chemical inertness and biochemical compatibility. Realization of some applications has been impeded by lack of a large area deposition method. By using a novel methodology to deposit graphene on solid and perforated substrates, various optoelectronic and biochemical elements have been demonstrated in this thesis: (1) graphene based transistors were fabricated and their characteristics were assessed. The mobility for such transistors exceeded 5000 cm2/V·s, much larger than their silicon based counterparts. Such attribute opens up new potential application in the field of very large scale integration (VLSI). (2) In parallel to vacuum tubes, where accelerated electrons are retained by a biased screen, a graphene based retaining electrode, placed in a wet-cell battery has stopped the battery’s current. In that respect, graphene proved to be a good ionic screening electrode because it does not oxidize easily. Applications could be in the field of ionic transistors and special electrochemical cells. (3) As surface pl asmon waveguides enter the electronic circuitry, surface plasmon sources are required. Graphene based surface pl asmons lasers were fabricated and characterized. Their attributes, illustrated by operational threshold, gain, spectral line narrowing and feedback at 630 nm all alluded to the action of a laser. Such, local pl asmonic sources may find applications in optoelectronic and sensor systems. (4) Infrared (IR) metal-mesh screens have been investigated as optical filters in the visible through the THz spectral region for astronomy and remote sensing applications. By interfacing these metal mesh screens with graphene, new spectroscopic platforms were fabricated. It has been shown that these platforms enhance I R and Raman signals of molecules and, specifically, signal of bio-species at the screens' surface. Biochemical sensing applications are envisioned. (5) Finally, the Raman spectra of molecules, deposited on graphene-coated nano-hole arrays have been investigated. It has been shown that these platforms were able to intensify such Raman signals, significantly. Potential usage of such platforms as biochemical sensors is envisioned.
Banerjee, Amrita, "Graphene-coated substrates for biochemical and optoelectronic applications" (2012). Dissertations. 330.