Monolithically integrated pixel architecture with colloidal quantum dots and thin film transistors for SWIR imaging

Infrared (IR) imaging, particularly in the short-wave infrared (SWIR) range, is important for applications such as remote sensing, biomedical diagnostics, and machine vision. Yet, widespread deployment remains constrained because today’s IR imaging primarily uses epitaxial III–V photodetectors, which deliver high responsivity and low dark current but require expensive, (nearly) lattice-matched substrates, high-temperature growth, and complicated hybrid integration of the focal plane array and ROIC. Alternatively, colloidal quantum dot (CQD) photodiodes are attractive for their solution processability with a tunable bandgap on large-area, low-cost crystalline or non-crystalline substrates. Here, we present a monolithic pixel architecture that integrates a PbS CQD photodiode in photovoltaic mode and an IGZO TFT in subthreshold mode. This configuration achieves a high optical-to-current conversion gain on the order of 10, 000 at 1060 nm wavelength with low dark current and over 1 MHz bandwidth to support a high frame rate. The demonstrated approach offers a scalable and manufacturable path toward low-cost SWIR imaging over large, panel-sized platforms.