Radiation-Hardened Position-Sensitive Photodetector Based on Undoped 4H-SiC.

Position-sensitive photodetectors (PSDs) have been widely used for seamless, high-resolution light tracking, but applications such as aerospace and prolonged field operations require stable performance in extreme environments. Conventional PSDs, typically based on the lateral photovoltaic effect of silicon or other semiconductor junctions, are prone to radiation damage and material degradation, limiting their reliability under harsh conditions. Silicon carbide (SiC), with its wide bandgap, high mobility, low defect density, and strong resistance to radiation damage, offers a promising alternative for developing robust detectors. In this work, we present a PSD based on undoped 4H-SiC, designed with a simple vertical structure that eliminates the need for complex multi-interface architectures. The device demonstrates excellent performance, including a light on-off ratio exceeding 10 under sub-milliwatt illumination, spatial resolution of ∼0.1 μm, and fast response times of ∼10 μs (rise) and ∼6.3 μs (fall). It also exhibits remarkable stability under γ-ray irradiation (300 krad) with minimal photocurrent variation, making it suitable for accurate position tracking in radiation-prone environments. This work highlights the potential of 4H-SiC-based PSDs for advanced sensing applications that demand both high performance and resilience in extreme environments.