Layer-dependent exciton polarizability and the brightening of dark excitons in few-layer black phosphorus
arXiv:2309.10327 · doi:10.1038/s41467-023-41126-8
Abstract
The evolution of excitons from 2D to 3D is of great importance in photo-physics, yet the layer-dependent exciton polarizability has not been investigated in 2D semiconductors. Here, we determine the exciton polarizabilities for 3- to 11-layer black phosphorus-a direct bandgap semiconductor regardless of the thickness-through frequency-resolved photocurrent measurements on dual-gate devices and unveil the carrier screening effect in relatively thicker samples. By taking advantage of the broadband photocurrent spectra, we are also able to reveal the exciton response for higher-index subbands under the gate electrical field. Surprisingly, dark excitons are brightened with intensity even stronger than the allowed transitions above certain electrical field. Our study not only sheds light on the exciton evolution with sample thickness, but also paves a way for optoelectronic applications of few-layer BP in modulators, tunable photodetectors, emitters and lasers.
30 pages, 4 figures
References in corpus (13)
- Two-Dimensional Material Nanophotonics
- Tunable optical properties of multilayers black phosphorus thin films
- Plasmons and screening in monolayer and multilayer black phosphorus
- Accessing the transport properties of pristine few-layer black phosphorus by van der Waals passivation in inert atmosphere
- Access and in situ Growth of Phosphorene-Precursor Black Phosphorus
- Infrared fingerprints of few-layer black phosphorus
- Surface Potentials and Layer Charge Distributions in Few-Layer Graphene Films
- Electric field screening in atomically thin layers of MoS2: the role of interlayer coupling
- Mid-infrared Electro-Optic Modulation in Few-layer Black Phosphorus
- Field Effect Optoelectronic Modulation of Quantum-Confined Carriers in Black Phosphorus
- The optical conductivity of few-layer black phosphorus by infrared spectroscopy
- Black phosphorus: A new bandgap tuning knob
- Strongly-bound excitons and trions in anisotropic 2D semiconductors