Device Engineering of Chalcogenide Photodiodes with Reduced Dark Current and Enhanced Stability for Underwater Light Communication

Abstract

Antimony based chalcogenides, such as Sb₂S₃ and Sb₂Se₃, have garnered attention in the fields of photovoltaics and photodetection due to their excellent optoelectronic properties, environmental stability, simple composition, and low-cost fabrication. However, most of the efficient Sb₂S₃- and Sb₂Se₃-based devices are fabricated based on organic materials as hole transport layer and costly metals as electrodes, which deteriorate the device stability, increase operational complexity and device fabrication cost. In this work, we propose the device engineering of Se and Sb to replace the organic interlayers and metal electrodes. An ultra-thin Sb₂Se₃ layer serves as the hole transport layer, formed through vacuum evaporation and in-situ annealing. This approach enhances charge transport capacity and reduces leakage current. The optimized Sb₂S₃ photodiodes exhibit exceptional performance metrics, including ultra-low dark current density, excellent specific detectivity, and superior stability even underwater, making them ideal for light communication. More importantly, this novel Se/Sb structure has been successfully extended to other chalcogenide semiconductor materials, showcasing significant potential for practical applications.