3D photodetecting structure with adjustable sensitivity ratio in UV–VIS range
Michael L. Korwin-Pawlowski
A 3D-photodetecting structure with adjustable sensitivity ratio in the ultra violet (UV) to visible (VIS) range is presented. The device is aimed for spectroscopic sensor applications. It consists of two photodiodes, silicon (Si), and silicon carbide (SiC), and an electronic circuit with switchable gains. The SiC photodiode is mounted in the centre of the Si photodiode. The SiC photodiode electronic channel can be used to adjust the sensitivity in the UV range, while the Si photodiode channel can be used for near UV and VIS sensitivity adjustment. Optical properties of the 3D-photodetecting structure are characterized using a deuterium broadband source and a halogen source and light emitted diodes at selected wavelengths. The proposed construction is similar to a matrix of independent UV and VIS detectors mounted on a common base, but the proposed integration method reduces the number of photodiodes and accompanying electronic circuits to minimum, which is an advantage especially when fibre optic applications are considered.