Dopamine-Sensing Characteristics and Mechanism by Using N₂/O₂ Annealing in Pt/Ti/n-Si Structure

Dopamine detection by using N2/O2 annealing in a Pt/Ti/n-Si structure is investigated for the first time. To achieve repeatable and stable dopamine detection, a Pt membrane is annealed at elevated temperatures of 500 to 700 °C. N2/O2 gas ambient is used to optimize the membrane. The Pt membrane with thicknesses from 5 to 2 nm is optimized. Novel Pt/Ti/n-Si Schottky contact in a metal–electrolyte–membrane–silicon (MEMS) structure detects dopamine with a low concentration of 1 pM. The Pt membrane with N2 ambient annealing shows the lowest concentration of dopamine sensing with a small volume of 10 µL, acceptable stability, and repeatability. Scan rate-dependent dopamine concentration sensing is also investigated in the two-terminal measurement method. This study is useful for the early diagnosis of Parkinson’s disease in the near future