Hadamard single-pixel imaging in the ultraviolet band based on a CdS/GaN heterojunction photodetector

The demand for ultraviolet (UV) photodetectors is increasing, and the breakthrough progress of 2D materials in the optoelectronic detection field has opened new avenues for UV imaging. However, traditional UV photodetectors often have slower response speeds, and fast response is crucial for single-pixel imaging (SPI). In this work, to achieve high-quality UV-band imaging, we utilized a high-performance CdS/GaN photodetector and designed an SPI system with Hadamard modulation. The photodetector demonstrated excellent optical response performance under UV light exposure. Under 0V bias and illumination with a 365 nm laser, the device exhibited a responsivity (<i>R</i>) of 2.4 mA/W, a detectivity (<i>D</i>*) of 1.34×10¹⁰ Jones, a current on/off ratio (<i>I</i>_on/<i>I</i>_off) of 475, and a response time of 626/769 µs. The imaging system demonstrated superior imaging capability, achieving high-quality object imaging even under low sampling rates (25% sampling rate). This study demonstrates the great potential of high-quality CdS/GaN self-powered photodetectors in computational imaging applications.