Novel Photosensitive\nDielectric-Based Image Sensor\nwith Both High Signal-to-Noise Ratio and High Fill Factor

Driven\nby the pursuit of a higher signal-to-noise ratio\n(SNR),\nCMOS imagers have evolved from initial passive pixel sensor (PPS)\nwith one transistor (1T) to 3T, 4T, or 5T active pixel sensors (APS)\nand then recently to digital pixel sensors (DPS). However, this evolution\ninevitably causes a lower and lower fill factor. Here, we innovatively\ndesigned a photodetector (PD) based on a photosensitive dielectric\n(PSD) strategy. The unique PSD layer works as an insulator in the\ndark and as a semiconductor under illumination, making the PD have\na built-in 4T function consisting of memory, address, amplification,\nand reset. Further, we prepared a 16 × 16 one-PD (1D) APS array\ndemo. The memory imaging, continuous imaging, power-off imaging, and\ntrajectory tracing imaging functionalities were successfully demonstrated.\nThis work provides a novel 1D APS structure with a built-in 4T function\nwell handling the SNR-fill factor trade-off, paving a new path for\na high-performance image sensor with good versatility and scalability.