| AVS 64th International Symposium & Exhibition | |
| 2D Materials Focus Topic | Thursday Sessions |
| Session 2D+AS+SS-ThA |
| Session: | Dopants, Defects, and Interfaces in 2D Materials |
| Presenter: | Kai Xiao, Oak Ridge National Laboratory |
| Authors: | K. Xiao, Oak Ridge National Laboratory X. Li, Oak Ridge National Laboratory M. Mahjouri-Samani, Oak Ridge National Laboratory M.-W. Lin, Oak Ridge National Laboratory L. Liang, Oak Ridge National Laboratory A. Oyedele, Oak Ridge National Laboratory M. Tian, University of Tennessee A.A. Puretzky, Oak Ridge National Laboratory J. Idrobe, Oak Ridge National Laboratory M. Yoon, Oak Ridge National Laboratory B.G. Sumpter, Oak Ridge National Laboratory G. Duscher, University of Tennessee C.M. Rouleau, Oak Ridge National Laboratory D.B. Geohegan, Oak Ridge National Laboratory |
| Correspondent: | Click to Email |
Two-dimensional (2D) materials are intrinsically heterogeneous, therefore controlling defects, understanding the impact of boundaries and interfaces, and developing means to exploit these heterogeneities is a transformative opportunity that could underpin future technologies and energy applications. This talk will discuss the fundamental understanding of the roles of heterogeneity, atomic interface, and disorder in 2D materials and their heterostructures. Through isoelectronic doping in monolayer of MoSe2, the Se vacancies are effectively suppressed and photoluminescence is significantly enhanced due to the decrease of defect-mediated non-radiative recombination. In addition, we demonstrate the non-equilibrium, bottom-up synthesis of single crystalline monolayers of 2D MoSe2−x with controllable levels of Se vacancies far beyond intrinsic levels. Both substitutional dopants and vacancies were shown to significantly alter the carrier properties and transport characteristics within a single monolayer (e.g., n- to p-type conduction in W-doped MoSe2 and in Se-deficient MoSe2-x). The vertical and lateral 2D heterostructures by controlled assembly and doping will be discussed. In addition, the lattice misfit heterostructures of monolayer GaSe/MoSe2 were synthesized by a two-step chemical vapor deposition (CVD) method. We find the vertically stacked GaSe/MoSe2 heterostructures maintain vdW epitaxy with well-aligned lattice orientation between the two layers, forming an incommensurate moiré superlattice. The bottom up synthesis of 2D materials discussed here provides excellent control over the heterogeneity in 2D materials, which can tunably modulate the optical and electrical properties in 2D materials and their heterostructure.
Acknowledgment: Synthesis science was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division and characterizations were performed at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility