Optoelectronic Properties of Layered Chalcogenide Semiconductors

Layered chalcogenide semiconductors, such as gallium and indium monochalcogenides, form van der Waals-bonded structures whose thickness-dependent electronic and optical properties have attracted intense interest. In the monolayer limit these materials often exhibit direct bandgaps spanning the visible to ultraviolet, strong excitonic resonances and pronounced in-plane anisotropy arising from low crystal symmetry. Advances in synthesis—from mechanical exfoliation and epitaxial growth to liquid-metal mediated deposition—have yielded wafer-scale and flexible films with precise thickness control. The interplay of quantum confinement, interlayer coupling and strain modulation underpins tunable photoluminescence, high photoresponsivity and giant nonlinear optical coefficients. Electrostatic gating and mechanical deformation provide further degrees of freedom to adjust conductivity and optical spectra. This versatile platform offers promising pathways for next-generation photodetectors, light-emitting diodes, nonlinear optical devices and integrated photonic circuits, with potential impact across sensing, optical communications and energy conversion.

Research from Nature Portfolio

Recent studies have introduced a quasi-layered domino-structured material that bridges traditional van der Waals layered crystals and non-layered systems. By combining covalent and van der Waals bonding in an oblique orientation, this material exhibits enhanced interlayer coupling, lattice distortions of up to 7.7% and a giant second-harmonic generation susceptibility approaching 394 pm V⁻¹, opening avenues in nonlinear photonics and anisotropic sensing. Another landmark investigation demonstrated gate-tunable giant anisotropic resistance in few-layer GaTe. Through electrostatic gating, the conductivity ratio along orthogonal in-plane directions can be modulated over three orders of magnitude, enabling directional memory devices and multifunctional nanoelectronic architectures. These advances highlight the power of symmetry breaking and external fields in tailoring optoelectronic responses of layered semiconductors.

Optoelectronic Properties of Layered Chalcogenide Semiconductors publication trend

The graph below shows the total number of articles in optoelectronic properties of layered chalcogenide semiconductors across all publications each year (not limited to Nature Index journals).

Technical terms

van der Waals forces: Weak interlayer interactions that enable stacking of two-dimensional layers while preserving individual layer integrity.

Bandgap: Energy difference between the valence and conduction bands that determines a semiconductor’s optical absorption and emission wavelengths.

Exciton: Bound electron–hole pair generated by photon absorption, crucial for light emission and absorption processes in low-dimensional systems.

Anisotropy: Direction-dependent variation of physical properties, often manifesting as different electrical or optical responses along in-plane axes.

Second-harmonic generation: Nonlinear optical process in which two photons combine to form a single photon at twice the incident frequency, sensitive to crystal symmetry.

References

1. 2D quasi-layered material with domino structure. Nature Communications (2023).
2. Gate tunable giant anisotropic resistance in ultra-thin GaTe. Nature Communications (2019).
3. Wafer‐Scale Two‐Dimensional Semiconductors for Deep UV Sensing. Small (2023).
4. Two-dimensional single crystal monoclinic gallium telluride on silicon substrate via transformation of epitaxial hexagonal phase. npj 2D Materials and Applications (2023).
5. Solution‐Processed GaSe Nanoflake‐Based Films for Photoelectrochemical Water Splitting and Photoelectrochemical‐Type Photodetectors. Advanced Functional Materials (2020).