Design and Characterization of a Novel MOS Photodetector for Chemiluminescence

Abstract

A compact MOS photodetector architecture integrating a vertical optical window and a catalytic microchamber has been developed as a proof-of-concept platform for chemiluminescence detection in aqueous media. The vertical trench sidewalls are designed to act as lateral optical windows, promoting photon propagation parallel to the depletion region and facilitating efficient absorption within a miniaturized footprint. This design enables chemiluminescence sensing without external illumination, supporting low-power operation and potential portability. Electrical measurements indicate a rectifying junction with a dark current in the lower nanoampere range, while optical characterization shows bias-dependent responsivity with optimal performance under moderate reverse bias, achieving 0.21 A/W at 470 nm (EQE similar to 57\%) and a subpicowatt NEP. Chemiluminescence experiments using luminol confirm stable photon detection, with normalized drift rates on the order of 0.3\%/min-1.7\%/min, decreasing to similar to 0.02\%/min after operation in aqueous conditions. These results support the feasibility of the proposed architecture as a compact, integrable platform for aqueous-phase chemiluminescent sensing.