Highly durable organic photodetector for complementary metal oxide semiconductor image sensors

Abstract

Utilizing organic electronics compatible with conventional semiconductor fabrication processes is extremely difficult because of their low chemical resistivity and poor environmental durability. To preserve the intrinsic functionality of organic materials, only a few fabrication processes can be used. Moreover, it is essential to achieve process expandability and silicon-process compatibility to develop high-resolution electronics suitable for mass production. Therefore, we developed wet-process-compatible organic photodetectors by replacing the conventional shadow-mask process with photolithography. This suppresses particle deposition during the serial fabrication processes, providing high operational stability. The fabricated green organic photodiodes exhibit a low dark current (1.0 × 10−11 A/cm2) with high photon–electron conversion efficiency (EQE = 65%). The charge collection and charge separation efficiencies are stable (ηcc = 84.6% and ηcs = 97.7%, respectively). Moreover, the organic semiconductors are compatible with conventional wet- and dry-etching processes owing to thin-film encapsulation layers. Finally, the novel organic image sensor can withstand 500 h under 85 °C/85% relative humidity and 1000 thermal cycles (−55–125 °C). Because of its robustness and strong barrier properties, the novel process architecture reported herein can be extended to any organic electronic devices, including widely commercialized organic light-emitting diodes and organic photovoltaic devices.