Scientific Achievement
Researchers in the Characterization of Functional Nanomachines Program demonstrated that the strength and mechanism of molecular diffusion can be tuned for 2D devices by altering the 2D carrier density and chemical potential.
Significance and Impact
Changing the gate voltage on a 2D field-effect transistor alters molecular diffusivity at the surface of the device by orders of magnitude, thus allowing 2D devices to be operated as diffusion switches.
Research Details
- Temperature-dependence of single-molecule diffusion on a 2D FET was tracked using scanning tunneling microscopy
- The diffusion barrier for neutral molecules was seen to increase linearly with reduced gate voltage. Charged molecules showed a reduced and constant diffusion barrier
- Ab initio calculations confirm these observations and show that completely different diffusion modes dominate for different molecular charge states
Publication Details
F. Liou, H. Tsai, Z.A.H. Goodwin, Y. Yang, A. S. Aikawa, B.R.P. Angeles, S. Pezzini, L. Nguyen, S. Trishin, Z. Cheng, S. Zhou, P.W. Roberts, X. Xu, K. Watanabe, T. Taniguchi, V. Bellani, F. Wang, J. Lischner, M. F. Crommie, ACS Nano (2024).
