Hybrid 2D-QD MoS2-PbSe Quantum Dot Broadband Photodetectors with High-Sensitivity and Room-Temperature Operation at 2.5 μm

Broadband infrared photodetectors have profound importance in diverse applications including security, gas sensing, bioimaging, spectroscopy for food quality, and recycling, just to name a few. Yet, these applications can currently be served by expensive epitaxially grown photodetectors, limiting their market potential and social impact. The use of colloidal quantum dots (CQDs) and 2D materials in a hybrid layout is an attractive alternative to design low-cost complementary metal-oxide-semiconductor (CMOS) compatible infrared photodetectors. However, the spectral sensitivity of these conventional hybrid detectors is restricted to 2.1 mu m. Herein, a hybrid structure comprising molybdenum disulfide (MoS2) with lead selenide (PbSe) CQDs is presented to extend their sensitivity further toward the mid-wave infrared, up to 3 mu m. A room-temperature responsivity of 137.6 A W-1 and a detectivity of 7.7 x 10(10) Jones are achieved at 2.55 mu m owing to highly efficient photoexcited carrier separation at the interface of MoS2 and PbSe in combination with an oxide coating to reduce dark current; the highest value is yet for a PbSe-based hybrid device. These findings strongly support the successful fabrication of hybrid devices, which may pave the pathway for cost-effective, high-performance, next-generation, novel photodetectors.

Automated summary

This study presents a hybrid structure consisting of molybdenum disulfide and lead selenide quantum dots to enhance the sensitivity of infrared photodetectors, extending it up to 3 micrometers in the mid-wave infrared range. The hybrid device exhibits a high responsivity and detectivity, paving the way for cost-effective, high-performance next-generation photodetectors.