| AVS 62nd International Symposium & Exhibition | |
| 2D Materials Focus Topic | Friday Sessions |
| Session 2D+EM+IS+NS+PS+SP+SS-FrM |
| Session: | Surface Chemistry of 2D Materials: Functionalization, Membranes, Sensors |
| Presenter: | Yao Zhou, Stanford University |
| Authors: | Y. Zhou, Stanford University E.J. Reed, Stanford University |
| Correspondent: | Click to Email |
Of the Mo- and W- dichalcogenide monolayers, MoTe2 is particularly interesting because it exhibits a small energy difference (approximately 31 meV per MoTe2) between its semiconducting 2H phase and metallic 1T’ crystal structures. This feature makes it particularly interesting for potential phase change applications.
We study the adsorption of some common atoms and molecules onto monolayer MoTe2 and the potential for adsorption to induce a phase change between the semiconducting 2H and metallic 1T’ crystal structures of the monolayer. Using density functional theory with spin orbit and van der Waals energy contributions, we determined the most energetically favorable adsorption positions and orientations on the two phases of monolayer MoTe2. We then obtained the formation energies for these adsorption reactions and found that atomic adsorption generally favors 1T’ metallic phases while molecular adsorption favors semiconducting 2H phases. A possible application of this work may be the chemical stabilization of a preferred phase during the growth process.
Further, we consider the MoxW1-xTe2 alloy monolayers that exhibit even smaller energy difference between phases. Our calculations indicate that it may be possible to engineer an alloy (0<x<0.5) such that specific molecules will induce a phase change to 1T’ while other molecules studied stabilize the 2H phase, which suggests that alloying may provide some molecular selectivity. This potentially provides the basis for molecular sensing applications due to the large electronic contrast between 2H and 1T’ phases.