M. Black
Advanced Silicon Group, Massachusetts, United States
Keywords: biosensing, protein sensors, silicon, multiplexing
We describe a novel modality for detecting molecules of interest present on a silicon surface in an aqueous solution via monitoring the change in the photocurrent as a response to surface passivation induced by the ionic state of the deposited molecules. This modality has unique advantages that make it well suited for cost sensitive applications that could benefit from a quantitative multiplexed test that has a low limit of detection. The experiments presented in this paper entail studying the influence of the protonation state of the 3-aminopropyltriethoxysilane (APTES) surface-deposited layer on the sensor operation by characterizing the surface passivation from the change in the photocurrent as well as external quantum efficiency (EQE). We also investigate the improvement of the detection signal resulting from an electric potential applied to the solution via an electrode that ideally perturbs the counterions on the device surface, and thus reduces charge screening.