Silver telluride colloidal quantum dot infrared photodetectors and image sensors

Photodetectors that are sensitive in the shortwave-infrared (SWIR) range (1–2 µm) are of great interest for applications such as machine vision, autonomous driving and three-dimensional, night and adverse weather imaging, among others. Currently available technologies in the SWIR range rely on costly epitaxial semiconductors that are not monolithically integrated with complementary metal–oxide–semiconductor electronics. Solution-processed quantum dots can address this challenge by enabling low-cost manufacturing and simple monolithic integration on silicon in a back-end-of-line process. So far, colloidal quantum dot materials to access the SWIR regime are mostly based on lead sulfide and mercury telluride compounds, imposing major regulatory concerns for their deployment in consumer electronics due to the presence of toxic heavy metals. Here we report a new synthesis method for environmentally friendly silver telluride quantum dots and their application in high-performance SWIR photodetectors. The colloidal quantum dot photodetector stack employs materials compliant with the Restriction of Hazardous Substances directives and is sensitive in the spectral range from 350 nm to 1,600 nm. The room-temperature detectivity is of the order of 1012 Jones, the 3 dB bandwidth is in excess of 0.1 MHz and the linear dynamic range is over 118 dB. We also realize a monolithically integrated SWIR imager based on solution-processed, toxic-heavy-metal-free materials, thus paving the way for this technology to the consumer electronics market. Silver telluride quantum dots are employed in shortwave-infrared photodetectors and in monolithically integrated imagers that are free from toxic heavy metals and fully solution processable.