| AVS 64th International Symposium & Exhibition | |
| 2D Materials Focus Topic | Thursday Sessions |
| Session 2D-ThP |
| Session: | 2D Materials Poster Session |
| Presenter: | Cameron Volders, University of Virginia |
| Authors: | C. Volders, University of Virginia E. Monazami, University of Virginia G. Ramalingam, University of Virginia P. Reinke, University of Virginia |
| Correspondent: | Click to Email |
The 2D material community has been dominated by Graphene, however, more recently, different single layer materials have garnered more attention including transition metal dichalcogenides (TMDs), silicene, and germanene. Silicene is particularly intriguing due to its potential for integration into silicon based devices. The most frequently used method for synthesizing silicene has been the deposition of monolayer (ML) amounts of Si onto Ag (111). The resulting layer(s) exhibit a honeycomb symmetry, which have been identified as silicene. An alternative interpretation of the Si-Ag system suggests the formation of 2D Ag-Si surface alloy rather than the formation of a well-defined silicene layer.
Our work will present an approach, which offers an alternative pathway for growing silicene layers, based on the observation of a Silicene-like reconstruction (SLR) on the surface of hexagonal-MoSi2 crystallites. Scanning Tunneling Microscopy and Spectroscopy were the primary techniques used for this study. H-MoSi2 crystallites are grown by depositing Mo onto a Si (001) surface followed by annealing. These crystallites are terminated by the (0001) plane which is comprised of Si hexagons with a Mo atom residing in the center. Upon annealing, the Si atoms decouple from the underlying h-MoSi2 crystallites and a honeycomb pattern with the lateral dimensions of a low-buckled silicene structure is observed.
We first discuss the optimal parameter space where the SLR is consistently reproduced. This regime includes depositing 2-5 MLs of Mo onto a Si (001) substrate and annealing around 650 - 800˚C. In this regime the SLR structure is readily observed and the geometrical parameters are nearly identical to that of a (√3X√3) silicene superstructure. Additional features of the SLR such as a well-defined ‘rim’ structure and defect motif will also be discussed.
The area of the SLR structure is controlled by the surface area of the h-MoSi2 crystallites, therefore, the second portion of this work will discuss how to control the size and distribution of these crystallites, thus the area of the SLR layer. This becomes critical for future device integration and assessing the detailed bonding structure with AR-UPS.
We would like to thank the Office of Naval Research for supporting this work.
(1) Volders, C.; Monazami, E.; Ramalingam, G.; Reinke, P. Alternative Route to Silicene Synthesis via Surface Reconstruction on h-MoSi2 Crystallites Nano. Lett. 2017, 17, 299-307.