Self-Filtered NIR Photodetectors Based on Silicon Micro-Holes Array for Stable Heart Rate Monitoring

Abstract

Here, we presented a novel near-infrared (NIR) photodetectors based on Si micro-holes array/graphene (SiMHs/Gr) Schottky barrier diode (SBD) for monitoring heart rate. The SBD exhibited a unique self-filtered NIR response in a range from 900 nm to 1160 nm with a responsivity of 122 mA/W at zero bias voltage. Moreover, our device possessed an ultrahigh signal to noise ratio (SNR) of more than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{5}}$ </tex-math></inline-formula> between visible and NIR light. The presented self-filtered NIR photodetector was used as a non-contact transmission-type photoplethysmography sensor for real-time heart rate monitoring. Due to the suppression of disturbances caused by ambient light, our device performed more accurate heart rate monitoring than those extracted from commercial broadband photodetectors.