Dopamine sensing using a simple Pt/n-Si structure is investigated for the first time. Polycrystalline Pt membrane with a thickness of 3 nm in Pt/n-Si structure is observed by high-resolution transmission electron microscope image. This Pt/n-Si structure shows a good pH sensitivity of 0.58/pH by measuring current-time response at pH values from 2 to 10. Repeatable and stable sensing of dopamine with a low concentration of 10 pM are obtained. Dopamine with long concentration range of 10 pM to 1 μM is measured and the sensing mechanism is due to Schottky barrier height modulation through reduction-oxidation of Pt membrane in contact of dopamine. This study is useful for future early diagnosis of Parkinson's disease.
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