Micro-Transfer-Printing of Al2O3-Capped Short-Wave-Infrared PbS Quantum Dot Photoconductors

Quantum dots (QDs) have attracted considerable attention in the development of various optoelectronic applications. The scalable heterogeneous integration of high quality, yet stable QD films is required for low-cost devices based on these materials. Here, we demonstrate the transfer printing of microscale patterns of Al2O3-capped PbS QD films to realize large-scale integrated photodetector arrays with a first excitonic absorption peak at 2.1 mu m wavelength. The process provides a facile approach to selectively pick-and-print QD assemblies on device structures with high precision. Transfer-printed photoconductor devices were realized and characterized at low bias voltage and optical power. Under 10 nW surface normal illumination at 2.1 mu m wavelength, the responsivity of our devices obtained at 1 V bias reached a maximum value of 25 A/W and 85 A/W for PbS QD films of 88 and 140 nm thick, respectively. Our approach suggests new routes toward scalable and cost-effective integration of multiple high-quality QD stacks on electronic and optoelectronic circuits.

Publication year:2019