Short-wave infrared position-sensitive detector enabled by lateral diffusion of thermalized carriers in lead salts

Position-sensitive detector (PSD) plays a vital role in various applications, such as motion tracking, pilotless automobile, laser radars, and precision machining. However, limited by the detection designs of the lateral photovoltaic effect and segmented sensors, the state-of-the-art PSD suffers from complicated architecture, slow response, and narrow waveband. Herein, we propose a conceptually distinct PSD operated in short-wave infrared (SWIR, 0.8–2.3 μm), an important optical communication waveband and atmosphere window, in single crystalline lead salts thin film. The SWIR PSD present self-driven (0 V bias), fast response (590 ns), and high position resolution (45.8 nm/Hz) with a position sensitivity of 257.8 mV/mm. By combining with the numerical simulation, the underlying physics of lateral thermalized carrier diffusion driven by temperature gradient is proposed to explain the ultrafast and high-resolved SWIR PSD. Finally, we demonstrate its applications in infrared target real-time tracking, indicating its great potential in infrared guidance, trajectory tracking, and microrobots.