CMOS-compatible Self-powered Short-wave Infrared Imagers Based on GeSn Photodetector Arrays

Group-IV GeSn alloys have emerged as a promising platform for short-wave infrared (SWIR) photodetection and imaging, owing to their tunable bandgap and compatibility with standard complementary metal–oxide–semiconductor (CMOS) processing. A self-powered, CMOS-compatible SWIR image sensor based on 4 × 4 GeSn p–i–n heterojunction photodetector pixel arrays (PDAs) monolithically integrated onto a Si platform is reported. Incorporating 6.3% Sn reduction in the direct bandgap, expansion of the photodetection range up to 2100 nm was achieved. The fabricated GeSn PDAs exhibit a peak detectivity of approximately 1.06 × 109 cm Hz1/2 W–1, surpassing the performance of commercially available PbSe and InSb IR PDs in uncooled conditions. Moreover, SWIR images are successfully obtained by using the self-powered GeSn PDAs, demonstrating their capability under both self-powered and uncooled conditions. This research paves the way for the development of CMOS-compatible, high-performance, cost-effective, and energy-efficient SWIR imaging and cameras for a range of previously unexplored SWIR applications.