Bias-Switchable Photodetector from Broad-Band to UV-Selective Detection Mode Leveraging Nanolayered Dual-Schottky Junction

The limitless potential of ultraviolet (UV) information is fueling the development of photodetecting technology beyond color image acquisitions such as air pollution monitoring, oil spill detection, and missile tracking systems. Ideal detectors for such applications need to separately perceive UV and visible lights to maximize their functional versatility. However, traditional device structures (e.g., photodiodes and photoconductors) inevitably require expensive filters or supplementary devices to discriminate the light sources. This study aims to develop photodetectors that provide dual functionalities in a single-unit device without any filters. To this end, we propose a device configuration based on two Schottky diodes stacked antiparallel. The dual-Schottky junctions (DSJs) uniquely arrange the band structure within the device to selectively create photocurrent from the targeted wavelengths (UV/visible) of light and block the rest (visible/UV) by adjusting the bias polarity. In addition, we further demonstrate dual-spectral detection in real time by mapping UV and broad-band (UV + visible) light images in a single frame without the aid of supplementary filters or equipment. The filter-free system, capable of UV/visible discrimination, would pave the way for developing a universal and multimodal next-generation photodetector with enhanced detection rates.