Image sensors are a key component of artificial intelligence, yet traditional methods bond detector arrays to readout integrated circuits (ROICs), a process that adds complexity and cost. The ideal alternative—using raw materials to grow detectors directly on the ROIC from solution—has long been difficult to realize, because obtaining electronic-grade thin films through ROIC-compatible processes is challenging. On October 28, 2026, Tang Jiang's team at Huazhong University of Science and Technology published online in Nature a research paper titled "Monolithically and in situ integrated PbS infrared imagers." Inspired by biomineralization, the study proposes a monolithic in-situ integration (MISI) strategy, using a room-temperature aqueous process to directly grow a PbS detection layer on finished ROICs. Pb–OH coordination chemistry is used to regulate the release of active species, locking supersaturation within a narrow window of pH 11.2–11.3 so that nucleation occurs only at the circuit interface; temperature fluctuations are stabilized to ±5 mK and vibration noise is suppressed below 0.01 μm/s, enabling wafer-scale uniform growth. Imaging technology is the foundation of the modern information society, with vision accounting for about 83% of human perception. The core of any digital imager lies in the precise integration of the photodetector array with the ROIC—the former captures light and converts it into electrical signals, while the latter processes the electrical signals. The quality of this integration directly determines the performance, cost, and form factor of the entire image sensor. The integration of photodetector arrays with ROICs has gone through different technological landscapes. The most advanced approach uses Cu–Cu bonding to connect the photodetector array to the ROIC, as demonstrated in InGaAs imagers. Despite the great success of this approach, the requirement for sub-micron alignment accuracy under continuously shrinking pixel pitch sharply increases device complexity, cost, and yield challenges. Monolithic integration, defined as fabricating the photodetector array and the ROIC on a single substrate, can greatly simplify the integration process and reduce manufacturing cost, thus becoming a focus of advanced sensor development.
Here, inspired by the principles of biomineralization, the researchers demonstrate a method for monolithically and in situ integrating (MISI) high-performance lead sulfide (PbS) photodetectors on ROICs via a room-temperature aqueous process. By regulating Pb–OH complexation and suppressing environmental perturbations, they obtained quasi-single-crystal PbS films with excellent electronic properties (carrier density of approximately 2 × 10¹⁵ cm⁻³, mobility of 124 cm² V⁻¹ s⁻¹) and wafer-level, pixel-level uniformity. Through antimony doping, the resulting photodiodes exhibit a record specific detectivity of 4.4 × 10¹¹ Jones at 2.5 µm, surpassing commercial InGaAs detectors. A 640 × 512 pixel focal plane array was further fabricated, capable of capturing clear infrared images, and the devices were directly integrated onto flexible ROICs. This solution-based MISI method provides a scalable and transformative pathway for advanced optoelectronics and sensors.
Reference: https://www.nature.com/articles/s41586-026-11222-y