Bi<sub>2</sub>S<sub>3</sub>Electron Transport Layer Incorporation for High-Performance Heterostructure HgTe Colloidal Quantum Dot Infrared Photodetectors
Ji Yang, Yifei Lv, Ziyang He, Binbin Wang, Shi‐Wu Chen, Feng Xiao, Huicheng Hu, Mengxuan Yu, Huan Liu, Xinzheng Lan, Hsien‐Yi Hsu, Haisheng Song, Jiang Tang
Abstract
Infrared photodetectors (PDs) based on epitaxial semiconductors occupy the majority of the market, but their high cost from material growth and device integration limits their application fields. Colloidal quantum dots (CQDs) provide a high potential candidate for infrared PDs due to their unique infrared sensitivity, tunable physical and chemical properties, and good compatibility with readout integration circuits. In particular, HgTe CQD PDs have demonstrated a wide detection range from short-wave to long-wave infrared. Although significant progress has been achieved in HgTe CQD infrared PDs, they are still in the primary stage of QD synthesis and prototype device fabrication. Here, we develop a new p–i–n photodiode from the traditional p–i device structure. Bismuth sulfide (Bi 2 S 3 ) films were adopted as the electron transport layer, which could favor uniform absorber deposition, superior charge extraction, and suppressed interfacial loss. The Bi 2 S 3 -based photodiodes have achieved a room-temperature dark current density as low as 1.6 × 10 –5 A/cm 2 at −400 mV. Furthermore, their specific detectivity ( D *) achieves ∼10 11 Jones at room temperature.