Hardness of Infrared Nanocrystal-Based Photodiode to Irradiations for Space Applications

Abstract Infrared (IR) sensing is essential for space applications such as remote sensing and spectroscopy, where sensors must withstand harsh radiation environments. Traditional IR sensors rely on II–VI and III–V semiconductor thin films, but emerging technologies like colloidal nanocrystals (NCs) offer cost-effective and scalable alternatives. However, the current study dedicated to their radiation tolerance remains very limited, thus leaving their potential unclear. This study investigates the radiation hardness of short-wave infrared (SWIR) photodiodes based on HgTe/CdS core–shell NCs, focusing on their resilience to X-ray, high-energy proton, and He+ ion irradiations, key challenges for space missions. The HgTe/CdS NCs, known for their thermal stability and low dark current, were processed into a diode stack and subjected to irradiation. Using X-ray photoemission spectroscopy (XPS) and depth profiling, we correlated optoelectronic degradation with nanoscale chemical and structural modifications, such as anion oxidation and cation redistribution. These findings highlight the potential of colloidal NCs to operate in a harsh radiation environment.