Material Engineering and Interface Regulation in Sn:PbSe/ZnO Heterojunctions Toward High‐Performance, Stable, and Broadband Infrared Photodetection

High‐performance, broadband infrared photodetectors operating at room temperature are crucial for modern imaging, sensing, and communication systems. However, their development is hindered by the cryogenic cooling requirements of conventional narrow‐gap semiconductors and the stability issues of emerging low‐dimensional materials. Herein, a novel material engineering and interface regulation strategy for chalcogenide lead salt films is proposed. A high‐performance heterojunction photodetector is constructed by integrating an in situ oxidized co‐sputtered Sn‐doped PbSe film with a magnetron‐sputtered ZnO layer. This device exhibits an ultralow dark current density(∼40 pA cm − 2 ) and an ultra‐high signal‐to‐noise ratio(∼10 5 ), an exceptional specific detectivity(D*) of ∼1 × 10 10 Jones in the visible–near‐infrared range and exceeding 1 × 10 8 Jones at 3.5 µm, and a fast response time of hundreds of microseconds. Remarkably, it maintains over 90% of its initial performance after three months of unencapsulated storage in air. This work lays the groundwork for future solution‐processed versions, provides a viable pathway toward stable and broadband infrared detection technology.