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Research Highlight

Isotopes Enable Major Improvement of Transport Properties in Two-Dimensional MoS2 Crystals

Isotopically Enhanced Materials
By replacing the mixture of naturally-occurring Mo (gray) in monolayer crystals of MoS2 with different pure isotopes (e.g., 92Mo (red) or 100Mo (green)) during growth, less defective crystals are formed and with 50% higher thermal conductivity.

Scientific Achievement

Synthesis of isotopically-pure MO in 2D MoS2 crystals resulted a 50% improvement in thermal conductivity.

Significance and Impact

By controlling isotopic disorder, properties from optoelectronic to thermal, can be tuned, thus providing a new means for optimization of 2D electronic devices.

Research Details

– Monolayer MoS2 crystals were synthesized with isotopically pure 100Mo and 92Mo precursors by chemical vapor deposition.

– A non-destructive optothermal Raman technique measured the in-plane thermal conductivity.

– First principles theory confirmed a ~15% improvement in thermal conductivity from a reduction in phonon scattering from different isotopes.

– Photoluminescence lifetime measurements revealed longer exciton lifetimes, indicating fewer crystal defects.

X. Li, J. Zhang, A. A. Puretzky, A. Yoshimura, X. Sang, Q. Cui, Y. Li, L. Liang, A. W. Ghosh, H. Zhao, R. R. Unocic, V. Meunier, C. M. Rouleau, B. G. Sumpter, D. B. Geohegan, K. Xiao, “Isotope-Engineering the Thermal Conductivity of Two-Dimensional MoS2," ACS Nano (2019). DOI. 10.1021/acsnano.8b09448