High-performance SWIR sensing from colloidal quantum dot photodiode arrays

RTI has demonstrated a novel photodiode technology based on IR-absorbing solution-processed PbS colloidal quantum dots (CQD) that can overcome the high cost, limited spectral response, and challenges in the reduction in pixel size associated with InGaAs focal plane arrays. The most significant advantage of the CQD technology is ease of fabrication. The devices can be fabricated directly onto the ROIC substrate at low temperatures compatible with CMOS, and arrays can be fabricated at wafer scale. Further, device performance is not expected to degrade significantly with reduced pixel size. We present results for upward-looking detectors fabricated on Si substrates with sensitivity from the UV to ~1.7 μm, compare these results to InGaAs detectors, and present measurements of the CQD detectors temperature dependent dark current.