Substrate-induced strain in 2D layered GaSe materials grown by molecular beam epitaxy

Cheng-Wei Liu; Jin-Ji Dai; Ssu-Kuan Wu; Nhu-Quynh Diep; Sa-Hoang Huynh; Thi-Thu Mai; Hua-Chiang Wen; Chi-Tsu Yuan; Wu-Ching Chou; Ji-Lin Shen; Huy-Hoang Luc

doi:10.1038/s41598-020-69946-4

Substrate-induced strain in 2D layered GaSe materials grown by molecular beam epitaxy

Sci Rep. 2020 Jul 31;10(1):12972. doi: 10.1038/s41598-020-69946-4.

Authors

Affiliations

¹ Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan.
² Department of Physics, Chung Yuan Christian University, Chung Li, 32056, Taiwan.
³ Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan. wuchingchou@mail.nctu.edu.tw.
⁴ Faculty of Physics, Hanoi National University of Education, Cau Giay, Hanoi, Vietnam.

Abstract

Two-dimensional (2D) layered GaSe films were grown on GaAs (001), GaN/Sapphire, and Mica substrates by molecular beam epitaxy (MBE). The in situ reflective high-energy electron diffraction monitoring reveals randomly in-plane orientations of nucleated GaSe layers grown on hexagonal GaN/Sapphire and Mica substrates, whereas single-orientation GaSe domain is predominant in the GaSe/GaAs (001) sample. Strong red-shifts in the frequency of in-plane [Formula: see text] vibration modes and bound exciton emissions observed from Raman scattering and photoluminescence spectra in all samples are attributed to the unintentionally biaxial in-plane tensile strains, induced by the dissimilarity of symmetrical surface structure between the 2D-GaSe layers and the substrates during the epitaxial growth. The results in this study provide an important understanding of the MBE-growth process of 2D-GaSe on 2D/3D hybrid-heterostructures and pave the way in strain engineering and optical manipulation of 2D layered GaSe materials for novel optoelectronic integrated technologies.