Low Dark-Current Quantum-Dot Infrared Imager

Taking advantage of tunable optical properties and silicon technique compatibility, colloidal quantum dots (CQDs) provide a simpler process for building infrared focal plane arrays (FPA) compared with traditional infrared bulk materials. So far, the CQD infrared FPA has been achieved, yet it faces the challenges of reducing dark current and noise. In this work, we achieve low dark-current and noise on the photoconductor by reducing energetic disorder and band tail in morphology-modified CQD solids. For the CQD infrared photoconductor at 2.0 μm, the dark current and noise of the shape-controlled CQD photoconductor are reduced by a factor of 25 and 10 at room temperature, respectively, compared with the reference device. Meanwhile, the sensitivity of the device is greatly improved when the specific detectivity reaches 4 × 1011 Jones. What’s more, the response time of the modified CQD photodetector is 0.94 μs, which is 100 times faster than the reference devices. To illustrate the flexible application of the CQD, we show a 640 × 512 pixel FPA imager at 2.0 μm with an operable pixel factor of 99.997% at 300 K. The reduced dark current could effectively suppress the overhot pixel count by 380 times.