Growth and Simultaneous Valleys Manipulation of Two-Dimensional MoSe2-WSe2 Lateral Heterostructure

Farman Ullah, Yumin Sim, Chinh Tam Le, Maeng Je Seong, Joon I. Jang, Sonny H. Rhim, Bien Cuong Tran Khac, Koo Hyun Chung, Kibog Park, Yangjin Lee, Kwanpyo Kim, Hu Young Jeong, Yong Soo Kim

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

The covalently bonded in-plane heterostructure (HS) of monolayer transition-metal dichalcogenides (TMDCs) possesses huge potential for high-speed electronic devices in terms of valleytronics. In this study, high-quality monolayer MoSe2-WSe2 lateral HSs are grown by pulsed-laser-deposition-assisted selenization method. The sharp interface of the lateral HS is verified by morphological and optical characterizations. Intriguingly, photoluminescence spectra acquired from the interface show rather clear signatures of pristine MoSe2 and WSe2 with no intermediate energy peak related to intralayer excitonic matter or formation of MoxW(1-x)Se2 alloys, thereby confirming the sharp interface. Furthermore, the discrete nature of laterally attached TMDC monolayers, each with doubly degenerated but nonequivalent energy valleys marked by (KM, K′M) for MoSe2 and (KW, K′W) for WSe2 in k space, allows simultaneous control of the four valleys within the excitation area without any crosstalk effect over the interface. As an example, KM and KW valleys or K′M and K′W valleys are simultaneously polarized by controlling the helicity of circularly polarized optical pumping, where the maximum degree of polarization is achieved at their respective band edges. The current work provides the growth mechanism of laterally sharp HSs and highlights their potential use in valleytronics.

Original languageEnglish
Pages (from-to)8822-8829
Number of pages8
JournalACS Nano
Volume11
Issue number9
DOIs
Publication statusPublished - 2017 Sep 26

    Fingerprint

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

Cite this

Ullah, F., Sim, Y., Le, C. T., Seong, M. J., Jang, J. I., Rhim, S. H., Tran Khac, B. C., Chung, K. H., Park, K., Lee, Y., Kim, K., Jeong, H. Y., & Kim, Y. S. (2017). Growth and Simultaneous Valleys Manipulation of Two-Dimensional MoSe2-WSe2 Lateral Heterostructure. ACS Nano, 11(9), 8822-8829. https://doi.org/10.1021/acsnano.7b02914