On‐Chip Weak‐Light Detection Using a Monolithically Integrated Perovskite Photodetector Array on LNOI Waveguides

ABSTRACT Inorganic perovskites are promising for photodetection due to their high stability and excellent optoelectronic characteristics. In this work, we present a high‐performance on‐chip photodetector array based on CsPbI 2 Br films monolithically integrated with lithium‐niobate‐on‐insulator (LNOI) waveguides. Operating at a wavelength of 638 nm under a 1 V bias, the device achieves a remarkable responsivity of 55 mA W − 1 , an ultra‐low dark current of 43 pA, and a high normalized photo‐dark current ratio (NPDR) of 10 9 W − 1 . Excellent uniformity performance is demonstrated across the on‐chip photodetectors array. These results underscore the synergistic combination of the perovskite's optoelectronic merits and their excellent compatibility with the LNOI platform, paving a promising path toward high‐efficiency, low‐cost, and scalable solutions for on‐chip weak‐light detection.