Tailoring optical and thermal properties in rare-earth doped MoS2 for device applications

The work presents a detailed account of the structural, optical, and thermal properties of ytterbium-doped molybdenum disulfide (MoS₂:Yb3+) thin films. The thin films were grown by femtosecond pulsed laser deposition technique. The thickness of the films was varied from 1–10 nm. The structural characterizations were performed using x-ray photoelectron spectroscopy, transmission electron microscopy, and Raman spectroscopy which reveal an enhancement of crystallinity and strain relaxation with increasing thickness. Temperature-dependent Raman spectroscopy indicates Yb3+-induced phonon anharmonicity, reflecting in-plane strain compensation and enhanced interlayer charge transfer. It is found that Yb3+ doping reduces thermal conductivity compared to pristine MoS₂, due to increased phonon scattering. The findings confirm the direct relationship between the changes in the lattice induced by the dopants and the phonon transport. This points to the fact that doping with rare earths together with control of thickness can modify the thermal and structural properties of two-dimensional materials. This work demonstrates co-engineering strategy of defects and thickness provides a scalable pathway that can be used for the production of functional MoS₂-based materials for next-generation applications of optoelectronics and heat management.