TU-TESL

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(photo source: photonics. Com) according to foreign media reports, a group of researchers from Pohang University of science and technology in South Korea have developed near-infrared (NIR) silicon photodiodes, which are one-third more sensitive than the existing photodiodes. The existing near-infrared photodiodes are usually made of chemical materials, which need separate cooling devices and are difficult to integrate. A group of researchers led by Professor Chang ki baek of Puxiang University of technology used hourglass silicon nanowires to increase the absorption of infrared light by silicon. Located above the nanowire, the inverted nanocone can extend the residence time of near infrared short wave infrared (SWIR) photons by producing echo wall resonance, while the lower one can reabsorb the incident light of the nearby nanowire due to its low reflectivity. Compared with the existing flat silicon photodiodes, the reaction of the nanowires to near-infrared light increases by 29% at the wavelength of 1000 nm. The researchers used the newly developed photodiode in the mobile heart rate measurement system, and found that compared with the existing photodiode, the sensitivity of the new photodiode is higher, and the error rate is less than 1%. Silicon used to make photodiodes can be mass produced at low cost. Potential applications include lidar, medical laser, night vision, image sensor, etc. used in autonomous vehicles.