Multispectral UV-Vis-IR imaging using low-cost quantum dot technology

Abstract

The current mainstay for short-wave infrared (SWIR) imaging is InGaAs-based focal plane arrays (FPAs). They provide excellent detectivity and low noise, but suffer from high costs, limited spectral response, and the same integration issues that limit array size for most inorganic FPA technologies. RTI has demonstrated a novel photodiode technology based on IR-absorbing, solution-processed colloidal quantum dots that can overcome the limitations of InGaAs FPAs. We have fabricated preliminary devices with quantum efficiencies exceeding 50%. These devices also show response times less than 10 μS, making them suitable for high speed imaging. The have demonstrated excellent linearity with over 40 dB of dynamic range. These devices are processed entirely at room temperature, and are compatible with monolithic integration onto readout ICs, thereby removing any limitation on device size. The process steps involve low-cost, high volume techniques that do not require sophisticated infrastructure, which should serve to dramatically reduce costs. This combination of high performance, dramatic cost reduction, and multispectral sensitivity is ideally suited to expand the use of SWIR imaging in current applications, as well as to address applications which require a multispectral sensitivity not met by existing technologies.