High-Performance Self-Powered UV Photodetectors Enabled by Diamond Homojunctions

Diamond is a highly suitable material for deep-ultraviolet photodetection due to its wide bandgap, strong radiation resistance, and exceptional thermal and chemical stability. Despite these advantages, most self-powered diamond-based ultraviolet photodetectors to date have relied on heterojunctions due to the difficulty of achieving n-type doping in diamond, which often introduces lattice defects and complicates the fabrication process. Here, we report a self-powered, solar-blind photodetector based on a diamond homojunction created by engineering a gradient in boron concentration to form a p+/p– junction. The device achieves excellent performance, including a high responsivity of 3.5 mA/W, rapid response times of 16 μs and 2.2 ms, a high detectivity of 1.13 × 1012 Jones, and an on/off ratio of ∼105 at 225 nm, exceeding those of most previously reported self-powered diamond ultraviolet photodetectors. Its functionality was further demonstrated in a single-line-pixel imaging system, successfully capturing high-contrast images. Our findings provide valuable insights for designing high-performance self-powered diamond ultraviolet photodetectors.