Optoelectronic Properties of Two-Dimensional Palladium Diselenide

Two-dimensional palladium diselenide (PdSe₂) exhibits a distinctive pentagonal lattice and pronounced in-plane anisotropy, yielding a narrow, tunable band gap that spans the near-infrared to visible spectrum. Atomically thin PdSe₂ is air-stable and combines sizeable charge-carrier mobility with strong light-matter interactions, including excitonic resonances and nonlinear optical phenomena. Layer number, strain and contact engineering permit systematic control of its electronic and optical response, underpinning applications in field-effect transistors, broadband photodetectors, frequency converters and flexible optoelectronic sensors. The material’s ability to maintain performance under ambient conditions further enhances its appeal for next-generation optoelectronic devices and integrated photonic circuits.

Research from Nature Portfolio

Recent studies have demonstrated that few-layer PdSe₂ field-effect transistors encapsulated in hexagonal boron nitride achieve high room-temperature mobilities (~700 cm²/V·s) and ultrahigh mobilities (~10 000 cm²/V·s) at cryogenic temperatures, revealing quantum oscillations characterised by twofold spin and fourfold valley degeneracies. Controlled magnetic fields can lift these degeneracies, yielding distinct quantum Hall spin and orbital ferromagnetic phases. Investigations into nonlinear optics have shown that monolayer to trilayer PdSe₂ possesses a unique thickness-dependent second-harmonic generation efficiency and exceptionally large two-photon absorption coefficients, with modulation depths exceeding 20 %, pointing to all-optical switching and frequency-conversion applications in the near-infrared. First-principles and experimental work on pentagonal PdSe₂ monolayers under tensile strain has further elucidated a strong strain–band-gap coupling, demonstrating that modest strain can redshift the intrinsic ~0.78 eV gap and significantly enhance infrared absorption for tunable photodetection and solar-energy conversion.

Optoelectronic Properties of Two-Dimensional Palladium Diselenide publication trend

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

Technical terms

Band gap: Energy difference between the valence and conduction bands, determining the wavelengths of light a semiconductor can absorb or emit.

Field-effect mobility: Measure of how quickly charge carriers move through a semiconductor channel under an applied electric field.

Exciton: Bound electron-hole pair formed when a photon excites an electron, critical for light absorption and emission processes.

Second-harmonic generation: Nonlinear optical process in which two photons combine to produce a new photon at twice the original frequency.

Two-photon absorption: Nonlinear process whereby two photons are simultaneously absorbed to excite an electron across the band gap.

Polarization sensitivity: Ability of a material or device to distinguish or preferentially respond to the orientation of the electric field in incident light.

Responsivity: Ratio of the electrical output (current or voltage) to the incident optical power, indicating detector efficiency.

Specific detectivity: Figure of merit for photodetectors, defined as the inverse of noise-equivalent power per unit area and bandwidth, indicating the weakest signal that can be detected.

References

1. Quantum octets in high mobility pentagonal two-dimensional PdSe2. Nature Communications (2024).
2. Giant nonlinear optical activity in two-dimensional palladium diselenide. Nature Communications (2021).
3. Strain-Modulated Electronic Structure and Infrared Light Adsorption in Palladium Diselenide Monolayer. Scientific Reports (2017).
4. Multilayered PdSe2/Perovskite Schottky Junction for Fast, Self‐Powered, Polarization‐Sensitive, Broadband Photodetectors, and Image Sensor Application. Advanced Science (2019).
5. Layer-dependent optical and dielectric properties of centimeter-scale PdSe2 films grown by chemical vapor deposition. npj 2D Materials and Applications (2022).
6. A broadband, self-powered, and polarization-sensitive PdSe2 photodetector based on asymmetric van der Waals contacts. Nanophotonics (2023).
7. Exploring the air stability of PdSe2 via electrical transport measurements and defect calculations. npj 2D Materials and Applications (2019).