IEEE EDS Invited talk: “Solid State Photodetector and Image Sensor with Non-Avalanche Approach”

#photodetector, #image-sensor, #MOSFET

Abstract: Photodetectors that enable weak light detection can be found in numerous applications including biomedical imaging, chemiluminescence detection and scientific spectroscopy. Photomultiplier Tubes (PMTs), Avalanche Photodiodes (APDs), and Silicon Photomultipliers (SiPMs) or Single Photon Avalanche Photodiodes (SPADs) have been widely used. However, bulky and power-hungry PMTs have suffered from severe temperature drift and hence, are very sensitive to ambient environment. APDs and SiPMs are compact but they have high shot noise and strong temperature dependence of output. Recently, 3-D photodetectors based on non-crystalline silicon thin-film transistors were investigated and deployed for digital mammography, nevertheless, their narrow dynamic range cannot meet the requirements for many applications. Since 2019, we have developed a new type of solid state photodetector, so-called photodiode-body-biased MOSFET (PD-MOS) that enjoys both high gain and wide dynamic range. Different from APDs and PMTs using either avalanche or photomultiplication to achieve high gain, the high-gain mechanism in the PD-MOS lies in the photo-modulated body bias effect. However, noise and dark current are still kept high. Here, our approach to high SNR is improving the gain while reducing the noise by a photoelectric integrated device (PID) based on dual PD-MOSs with one dark-PD-MOS and the other light-PD-MOS. Furthermore, by tuning the gate bias of the light-PD-MOS, an adjustable gain of unity to 107 is attained together with a wide dynamic range over 160dB and a broad spectrum response from 254nm to 1300nm. Such performance characteristics have made it a great promise for many emerging applications, requiring low-level detection and imaging.

  Date and Time




  • Date: 19 Jun 2023
  • Time: 03:00 PM to 04:00 PM
  • All times are (UTC-07:00) Pacific Time (US & Canada)
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  • 8888 University Dr.
  • Burnaby, British Columbia
  • Canada V5A 1S6
  • Building: Applied Science Building
  • Room Number: ASB 10704

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Kai of School of Electronics and Information Technology at Sun Yat-Sen University


Solid State Photodetector and Image Sensor with Non-Avalanche Approach


Speaker biography: Kai Wang is with the School of Electronics and Information Technology at Sun Yat-Sen University (SYSU) in Canton, China. He earned his Ph. D. degree from the University of Waterloo in 2008 and was thereafter appointed as a NSERC postdoctoral fellow at Thunder Bay Health Science Centre where he conducted research on large area imaging until he joined Apple Inc. as a senior hardware development engineer in 2011. He then worked in the Department of Electrical and Computer Engineering at Carnegie Mellon University (CMU) as a visiting professor in 2014 before joining SYSU-CMU Joint Institute of Engineering (JIE) where he was one of the founding faculty members in Microelectronics program. In 2017, he became a full professor and was also cross-appointed by the State Key Laboratory of Optoelectronic Materials and Technologies (SKL-OMET) to direct the image sensor research. His current research focuses on optical and image sensors and human-machine interfaces. He has published over 100 journal papers/conference proceedings and coauthored over 30 patents, many of which have been transferred to industry and leading to two start-up companies.