Black phosphorus-based van der Waals heterostructures for mid-infrared light-emission applications

Xinrong Zong,Wei Huang,Le Zhang,Shouheng Chen,Bing Wang,Zheng Liu,Xiaolong Chen,Chao Zhu,Run Shi,Lin Wang,Jingwei Wang,Gang Ouyang,Qingsheng Zeng,Huamin Hu,Chun Cheng,Taihong Wang,Han Zhang

doi:10.1038/s41377-020-00356-x

Abstract

Mid-infrared (MIR) light-emitting devices play a key role in optical communications, thermal imaging, and material analysis applications. Two-dimensional (2D) materials offer a promising direction for next-generation MIR devices owing to their exotic optical properties, as well as the ultimate thickness limit. More importantly, van der Waals heterostructures—combining the best of various 2D materials at an artificial atomic level—provide many new possibilities for constructing MIR light-emitting devices of large tuneability and high integration. Here, we introduce a simple but novel van der Waals heterostructure for MIR light-emission applications built from thin-film BP and transition metal dichalcogenides (TMDCs), in which BP acts as an MIR light-emission layer. For BP–WSe2 heterostructures, an enhancement of ~200% in the photoluminescence intensities in the MIR region is observed, demonstrating highly efficient energy transfer in this heterostructure with type-I band alignment. For BP–MoS2 heterostructures, a room temperature MIR light-emitting diode (LED) is enabled through the formation of a vertical PN heterojunction at the interface. Our work reveals that the BP–TMDC heterostructure with efficient light emission in the MIR range, either optically or electrically activated, provides a promising platform for infrared light property studies and applications.

Highlights

We introduce a high-quality van der Waals heterostructure targeted for MIR light-emission applications constructed from thin-film black phosphorus (BP) and transition metal dichalcogenides (TMDCs), such as monolayer tungsten diselenide (WSe2) and thin-film molybdenum disulfide (MoS2)
Combining density functional theory (DFT) calculations[41] and experimental observations, a type-I band alignment is formed in the BP–WSe2 heterostructure, and efficient energy transfer from WSe2 to thin-film BP is enabled
All the results suggest that constructing BP–TMDC heterostructures is an efficient and facile strategy for MIR light-emission investigations and applications

Summary

Introduction

As an emerging member of the two-dimensional (2D)-layered material family, black phosphorus (BP)[1,2,3,4,5,6] has been widely studied for its unique properties, such as inplane anisotropy[5,7], infrared bandgap energy[8,9,10], and high carrier mobility[11,12,13,14], which enable wide applications in electronic and optoelectronic devices[15,16]. We introduce a high-quality van der Waals (vdWs) heterostructure targeted for MIR light-emission applications constructed from thin-film BP and TMDCs, such as monolayer tungsten diselenide (WSe2) and thin-film molybdenum disulfide (MoS2). Combining density functional theory (DFT) calculations[41] and experimental observations, a type-I band alignment is formed in the BP–WSe2 heterostructure, and efficient energy transfer from WSe2 to thin-film BP is enabled.

Results

Conclusion