Deep-Level Impurity Enabled Planar Filterless Narrowband Near-Infrared Si Photodetector

Near-infrared narrowband photodetectors are extensively used in fire alarms, industrial process control, diagnosis of heating systems, etc., owing to their strong anti-interference ability and high thermal sensitivity. In this study, a near-infrared narrowband Si photodetector with a simple Schottky structure was developed via deep-level Au-atom doping to control the recombination processes of the photogenerated carriers. The wavelength selectivity and sensitivity of the device were effectively tuned by modulating both the doping temperature and incident angle. Its peak detectivity at 1080 nm was $1.84\times 10^{{12}}$ Jones with a full-width at half-maximum of 101 nm, and the −3 dB bandwidth of the device was estimated to be 4.6 kHz (rise time of $22~\mu \text{s}$ and fall time of $74~\mu \text{s}$ ). Furthermore, owing to its planar structure and simple fabrication process, the present narrowband photodetector can be easily combined with other broadband photodiodes to effectively map the high-temperature area of a target object and provide further temperature-gradient change information. This study opens up a new avenue for developing planar-type narrowband photodetectors suitable for on-chip application in next-generation near-infrared optoelectronic systems.