Defect Engineering in Two-Dimensional Materials

Two-dimensional materials, exemplified by graphene and transition metal dichalcogenides (TMDs), exhibit exceptional electronic, optical and catalytic properties arising from their atomically thin structures. Intrinsic and intentionally introduced defects—ranging from vacancies and substitutional heteroatoms to extended dislocations—offer powerful levers to tune charge transport, light–matter interactions and chemical reactivity. By controlling defect type, concentration and spatial arrangement through methods such as chemical vapour deposition, ion irradiation and post-growth annealing, researchers can achieve enhanced photoluminescence, modulated bandgaps, single-photon emission and tailored catalytic activity. Defect engineering not only mitigates performance limitations caused by unintentional imperfections but also creates novel functionalities unattainable in pristine crystals. As the community advances scalable synthesis and in situ characterisation techniques, a deeper understanding of defect formation energies, migration pathways and electronic signatures is emerging. This progress paves the way to engineered two-dimensional architectures for next-generation electronics, optoelectronics and energy conversion technologies.

Research from Nature Portfolio

Recent studies have employed deep level transient spectroscopy combined with atomic-scale imaging to elucidate the energy levels and interactions of vacancy clusters in monolayer molybdenum disulfide. This work revealed that neighbouring sulphur-vacancy pairs, though a minority, dominate off-state currents and switching slopes in field-effect devices by introducing shallow hybridised trap states. In a complementary investigation, controlled in-vacuo annealing and focused ion beams were used to generate chalcogen vacancies in monolayer MoS2, whose optical signatures were resolved into narrow defect-bound photoluminescence peaks. These vacancies, patterned with nanometre precision, exhibit single-photon emission and open routes to integrated quantum light sources. Together, these contributions advance quantitative defect characterisation and precision patterning at the ultimate scale in two-dimensional semiconductors.

Defect Engineering in Two-Dimensional Materials publication trend

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

Technical terms

Vacancy: An absent atom in the crystal lattice that can localise charge and modify electronic states.

Substitutional defect: A foreign atom replacing a host atom, introducing localised energy levels or strain.

Chemical vapour deposition (CVD): A synthesis technique in which gaseous precursors react at a heated substrate to form thin films.

Deep level transient spectroscopy (DLTS): An electrical characterisation method that measures carrier emission rates from defect states.

Photoluminescence: The emission of light following radiative recombination of photo-excited charge carriers.

Exciton: A bound electron–hole pair whose dynamics influence optical and electronic responses in semiconductors.

References

1. Defect engineering of two-dimensional transition metal dichalcogenides. 2D Materials (2016).
2. Electrical spectroscopy of defect states and their hybridization in monolayer MoS2. Nature Communications (2023).
3. The role of chalcogen vacancies for atomic defect emission in MoS2. Nature Communications (2021).
4. Oxygen Driven Defect Engineering of Monolayer MoS2 for Tunable Electronic, Optoelectronic, and Electrochemical Devices. Advanced Functional Materials (2024).
5. Two-dimensional MoS2 under ion irradiation: from controlled defect production to electronic structure engineering. 2D Materials (2017).
6. A Review on Lattice Defects in Graphene: Types, Generation, Effects and Regulation. Micromachines (2017).