Substrate Lattice-Guided Seed Formation Controls the Orientation of 2D Transition Metal Dichalcogenides
MetadataShow full item record
AbstractTwo-dimensional (2D) transition metal dichalcogenide (TMDCs) semiconductors are important for next-generation electronics and optoelectronics. Given the difficulty in growing large single crystals of 2D TMDC materials, understanding the factors affecting the seed formation and orientation becomes an important issue for controlling the growth. Here, we systematically study the growth of molybdenum disulfide (MoS2) monolayer on c-plane sapphire with chemical vapor deposition (CVD) to discover the factors controlling their orientation. We show that the concentration of precursors, i.e., the ratio between sulfur and molybdenum oxide (MoO3), plays a key role in the size and orientation of seeds, subsequently controlling the orientation of MoS2 monolayers. High S/MoO3 ratio is needed in the early stage of growth to form small seeds that can align easily to the substrate lattice structures while the ratio should be decreased to enlarge the size of the monolayer at the next stage of the lateral growth. Moreover, we show that the seeds are actually crystalline MoS2 layers as revealed by high-resolution transmission electron microscopy. There exist two preferred orientations (0° or 60°) registered on sapphire, confirmed by our density functional theory (DFT) simulation. This report offers a facile technique to grow highly aligned 2D TMDCs and contributes to knowledge advancement in growth mechanism.
CitationAljarb A, Cao Z, Tang H-L, Huang J-K, Li M, et al. (2017) Substrate Lattice-Guided Seed Formation Controls the Orientation of 2D Transition Metal Dichalcogenides. ACS Nano. Available: http://dx.doi.org/10.1021/acsnano.7b04323.
SponsorsAll authors acknowledge support from King Abdullah University of Science and Technology (KAUST) under Competitive Research Grant (#CRG4-2634) and KAUST Catalyst Center, Saudi Arabia. The simulations were performed on the Shaheen II supercomputer.
PublisherAmerican Chemical Society (ACS)
- Step-Edge-Guided Nucleation and Growth of Aligned WSe2 on Sapphire via a Layer-over-Layer Growth Mode.
- Authors: Chen L, Liu B, Ge M, Ma Y, Abbas AN, Zhou C
- Issue date: 2015 Aug 25
- Seed Crystal Homogeneity Controls Lateral and Vertical Heteroepitaxy of Monolayer MoS2 and WS2.
- Authors: Yoo Y, Degregorio ZP, Johns JE
- Issue date: 2015 Nov 18
- Metal seed layer thickness-induced transition from vertical to horizontal growth of MoS2 and WS2.
- Authors: Jung Y, Shen J, Liu Y, Woods JM, Sun Y, Cha JJ
- Issue date: 2014 Dec 10
- Unravelling orientation distribution and merging behavior of monolayer MoS2 domains on sapphire.
- Authors: Ji Q, Kan M, Zhang Y, Guo Y, Ma D, Shi J, Sun Q, Chen Q, Zhang Y, Liu Z
- Issue date: 2015 Jan 14
- Lateral Versus Vertical Growth of Two-Dimensional Layered Transition-Metal Dichalcogenides: Thermodynamic Insight into MoS2.
- Authors: Shang SL, Lindwall G, Wang Y, Redwing JM, Anderson T, Liu ZK
- Issue date: 2016 Sep 14