Electrochemical biosensor devices often utilize gold thin films as working electrodes. The aim of my work was to characterize the changes in the surface structure of these gold films after thermal annealing procedures. My final goal would be to achieve almost atomically flat areas with sufficient size using only simple annealing methods.
These flat areas could provide excellent material for inspecting immobilized biomolecules (like DNA-molecules) with the help of atomic force microscopy, giving a valuable tool for biosensor and medical science.
To reach my goal, I gathered information from the literature according to thermal annealing strategies, and implemented them taking into account the available infrastructure and possibilities. I inspected the structural changes of different samples after annealing them with various parameter (for example atmosphere, time and temperature) combinations.
I determined the indispensable factors for creating almost atomically flat areas on the surface, such as the inert atmosphere. In nitrogen atmosphere, with a 5 minutes long thermal annealing at 360 °C I successfully created parcels, 1 µm in diameter with an average surface roughness of only 1.1 nm, which was my best result in all the thermal annealing processes.