# Large-area Epitaxial Monolayer MoS2

**Authors:** Dumitru Dumcenco, Dmitry Ovchinnikov, Kolyo Marinov, Oriol Lopez-Sanchez, Daria Krasnozhon, Ming-Wei Chen, Philippe Gillet, Anna Fontcuberta i Morral, Aleksandra Radenovic, Andras Kis  
**arXiv:** [1405.0129](https://arxiv.org/abs/1405.0129)  
**Date:** 2014-05-01  
**Summary page:** https://www.summarizepaper.com/en/paper/1405.0129v1/

## Key points

- Two-dimensional semiconductors like MoS2 have potential for various applications in electronics, optoelectronics and energy harvesting.
- Large-area growth methods are required to enable their practical use.
- Controlling the lattice orientation during growth remains a challenge.
- Grain boundaries can form during growth and negatively impact the electrical, optical and mechanical properties of MoS2 and other 2D semiconductors.
- The authors report on the uniform growth of high-quality centimeter-scale continuous monolayer MoS2 with control over lattice orientation using an epitaxial growth mechanism.
- Raman and photoluminescence spectra confirm the high quality of the grown material.
- Optical absorbance spectra acquired over large areas show new features in the high-energy part of the spectrum, indicating that MoS2 could also be interesting for harvesting this region of the solar spectrum and fabrication of UV-sensitive photodetectors.
- The interaction between the growth substrate and MoS2 is strong enough to induce lattice alignment; however, it is still possible to transfer the grown material easily and fabricate field-effect transistors on SiO2 substrates showing mobility superior to exfoliated material.
- The authors suggest that their findings could pave the way for further research into large-scale production techniques for 2D materials with controlled crystallographic orientations.

## Summary

Two-dimensional semiconductors, such as MoS2, have shown great potential for various applications in electronics, optoelectronics and energy harvesting. However, large-area growth methods are required to enable their practical use. Although significant progress has been made towards this goal, controlling the lattice orientation during growth remains a challenge. Grain boundaries can form during growth and negatively impact the electrical, optical and mechanical properties of MoS2 and other 2D semiconductors. In this study, the authors report on the uniform growth of high-quality centimeter-scale continuous monolayer MoS2 with control over lattice orientation. Using transmission electron microscopy, they show that the monolayer film is composed of coalescing single islands that share a predominant lattice orientation due to an epitaxial growth mechanism. Raman and photoluminescence spectra confirm the high quality of the grown material. Optical absorbance spectra acquired over large areas show new features in the high-energy part of the spectrum, indicating that MoS2 could also be interesting for harvesting this region of the solar spectrum and fabrication of UV-sensitive photodetectors. The interaction between the growth substrate and MoS2 is strong enough to induce lattice alignment; however, it is still possible to transfer the grown material easily and fabricate field-effect transistors on SiO2 substrates showing mobility superior to exfoliated material. The authors suggest that their findings could pave the way for further research into large-scale production techniques for 2D materials with controlled crystallographic orientations. Overall, this study provides important insights into how to grow high-quality 2D materials with controlled crystallographic orientations at a large scale which could have significant implications for future research in electronics, optoelectronics and energy harvesting fields using these materials.