Image sensors and cameras based on colloidal quantum dots (CQD) for visible-to-SWIR detection

Image sensors made using colloidal quantum dots (CQDs) as the optical absorber material are breaking through as a viable competing technology within the SWIR and MWIR imaging domains. The CQD-based absorber material stack is processed directly onto the surface of the CMOS wafer providing advantages in scalability, cost and flexibility regarding pixel size and dimensions. The absorption spectrum can be tailored by choice of quantum dot size and material system for the same underlying read-out integrated circuit (ROIC). Here, we introduce the Emberion image sensor platform and report our recent results on image sensor development using Lead Sulfide (PbS) CQDs processed onto our custom-designed ROIC. The optoelectronic characteristics of the CQD photosensitive stack are analyzed and the optimal interface to the ROIC is discussed. We also address challenges related to manufacturability such as the planarity requirements of the ROIC surface to facilitate wet-processing via spin-cast CQD thin-film layers. We demonstrate wavelength response from 400 nm out to beyond 2000 nm with noise equivalent irradiance (NEI) below 1e-3 W/m2 over the entire spectral range. Selected illustrative application demonstrations are showcased including detection of water content at SWIR wavelengths, high-speed imaging of a moving target at 400 fps and camouflage detection.