Plasmonic Enhancements in Two-Dimensional Optoelectronic Materials

Atomically thin semiconductors such as transition metal dichalcogenides and graphene exhibit exceptionally strong light–matter interactions but are hindered by intrinsically low optical absorption and emission due to their sub‐nanometre thickness. Plasmonic nanostructures, which confine and amplify electromagnetic fields at metal–dielectric interfaces, offer a route to overcoming these limitations. By exploiting localised surface plasmon resonances in noble-metal nanoparticles or gap plasmons in nanometre-scale trenches, researchers have demonstrated orders-of-magnitude improvements in photoluminescence intensity, spontaneous emission rates and directional out-coupling. Complementary approaches using high-index dielectric nano-antennas achieve low-loss field confinement and enhanced Purcell factors without metallic dissipation. Integration of these plasmonic and dielectric elements with monolayer semiconductors enables on-chip nanolasers, highly sensitive photodetectors, tunable light emitters and compact optical modulators. The convergent developments in nanofabrication, computational design and materials synthesis have ushered in a new era of hybrid optoelectronic platforms, with potential impact on energy harvesting, information processing and quantum photonics.

Research from Nature Portfolio

Recent studies have demonstrated the feasibility of giant photoluminescence enhancements in atomically thin semiconductors via judiciously engineered metal nanostructures. In one work, monolayer tungsten diselenide suspended over sub-20 nm trenches in a gold film exhibited lateral gap plasmons that boosted absorption and spontaneous emission, yielding a ∼20 000-fold increase in photoluminescence intensity. A second investigation realised low-loss gallium phosphide nano-antennas coupled to monolayer WSe₂, achieving >10⁴-fold photoluminescence enhancement through combined Purcell-factor increase, improved excitation efficiency and tailored emission directionality, along with polarisation-dependent control and Raman signal amplification. Foundational work on gold-nanorod arrays overlaying monolayer molybdenum disulfide revealed that optimised nanoparticle coverage creates spectral and spatial overlap between the localised plasmon resonance and the MoS₂ emission spectrum, leading to tunable photoluminescence enhancements up to an order of magnitude and a clear understanding of quenching-threshold effects.

Plasmonic Enhancements in Two-Dimensional Optoelectronic Materials publication trend

The graph below shows the total number of articles in plasmonic enhancements in two-dimensional optoelectronic materials across all publications each year (not limited to Nature Index journals).

Technical terms

Surface plasmon polariton (SPP): Electromagnetic wave coupled to collective electron oscillations at a metal–dielectric interface, enabling subwavelength field confinement.

Localised surface plasmon resonance (LSPR): Resonant oscillation of conduction electrons in metal nanoparticles that produces intense near-field enhancement and spectral selectivity.

Purcell factor: Measure of the enhancement of spontaneous emission rate of a quantum emitter in the presence of a resonant cavity or antenna relative to free space.

Transition metal dichalcogenide (TMD): Layered semiconductor with formula MX₂ (M = transition metal, X = chalcogen) exhibiting strong excitonic effects in the monolayer limit.

Photonic cavity: Optical resonator that confines light in space and frequency, increasing light–matter interaction by prolonging photon dwell time.

Photoluminescence (PL): Emission of light from a material following optical excitation, used to probe electronic and excitonic properties.

Exciton: Bound state of an electron and a hole in a semiconductor, responsible for much of the optical response in low-dimensional materials.

References

1. Giant photoluminescence enhancement in tungsten-diselenide–gold plasmonic hybrid structures. Nature Communications (2016).
2. Enhanced light-matter interaction in an atomically thin semiconductor coupled with dielectric nano-antennas. Nature Communications (2019).
3. Plasmonic Gold Nanorods Coverage Influence on Enhancement of the Photoluminescence of Two-Dimensional MoS2 Monolayer. Scientific Reports (2015).
4. Plasmonics of 2D Nanomaterials: Properties and Applications. Advanced Science (2017).
5. Enhancing light‐matter interaction in 2D materials by optical micro/nano architectures for high‐performance optoelectronic devices. InfoMat (2020).