Bonding of Shortwave\nInfrared Organic Photodetectors\non Silicon via Conducting Polymer Glue for Image Sensor Applications

Integrating organic photodetectors (OPDs) with silicon\n(Si)-based\nreadout integrated circuits presents numerous challenges, particularly\ndue to the degradation of organic semiconductors (OSCs) caused by\nvarious stresses. This issue is especially pronounced in narrow bandgap\nOSCs with shortwave infrared (SWIR) spectral responses, further complicating\nthe development of organic image sensors. To address the issue, we\ndraw inspiration from silicon- and germanium-based sensor technology,\nproposing a method of first fabricating bottom-illuminated SWIR OPD\ndevices on a glass substrate and then bonding the OPD onto a Si substrate\nusing a poly(3,4-ethylene­dioxythiophene):polystyrene­sulfonate\n(PEDOT:PSS) glue to form a top-illuminated device. This architecture\navoids exposing the OPDs to high temperatures and plasma bombardment\nduring the thin-film deposition, and the glass substrate can also\nserve as an ideal encapsulation cover, offering a new direction for\nthe integration of OPD-on-Si technology. Eventually, the bonded, top-illuminated\ndevice achieves a detectivity of 3.58 × 10<sup>10</sup> Jones\nat 1290 nm and −2 V bias. This advancement not only enhances\nthe integration completeness of OPDs with Si semiconductors but also\npreserves the intrinsic performance of OSC materials, further bringing\nrevolutionary changes to the organic sensing industry.