Broadband Photodetectors and Imaging Arrays Based on PtSe ₂ /Si Heterojunctions

ABSTRACT

Short‐wave infrared (SWIR) photodetectors are of great importance for applications such as optical communications. However, due to the bandgap limitation of silicon (Si) and the poor compatibility of many SWIR photoactive materials with conventional integrated‐circuit processes, the development of high‐performance, broadband SWIR photodetectors suitable for miniaturization and monolithic integration remains highly challenging. Herein, a visible‐to‐SWIR broadband photodetector based on a PtSe ₂ thin‐film/Si heterojunction is proposed, and an 8 × 8 array device is further demonstrated. Centimeter‐scale PtSe ₂ films with good uniformity are obtained by combining magnetron sputtering with subsequent selenization. Benefiting from a well‐engineered heterojunction band alignment, the PtSe ₂ /Si unit cell exhibits a high on/off ratio up to 3.61 × 10 ⁵ at −0.01 V with highly sensitive room‐temperature operation, including a broadband spectral response from 405 to 1550 nm, a specific detectivity of 2.58 × 10 ¹¹ Jones, and a microsecond‐level response speed. A dedicated readout circuit is further developed, enabling real‐time SWIR imaging. This work provides a scalable, CMOS‐compatible route toward room‐temperature sensitive SWIR detectors for next‐generation optoelectronic systems.