Domain engineering of epitaxial (001) Bi2Te3 thin films by miscut GaAs substrate. (15th September 2020)

• Record Type: Journal Article
• Authors: Kim, Kwang-Chon; Kim, Seong Keun; Kim, Jin-Sang; Baek, Seung-Hyub
• Is Part Of: Acta materialia. Volume 197(2020)
• Page Start: 309
• Page End: 315
• Publication Date: 2020-09-15
• Subjects: Bi2Te3 -- Epitaxial -- Domain engineering -- Miscut -- Thermoelectric; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2020.07.051
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: Herein, we have reported domain engineering of epitaxial (001) Bi2 Te3 thin films by miscut (100) substrates. On a nominal flat (100) GaAs substrate, two-variant domains that were in-plane rotated by 60°, including the 60° domain boundaries, were formed in the epitaxial Bi2 Te3 film, such that the symmetry elements of two-fold rotational and/or mirror symmetries of the GaAs substrate were preserved. The domain variants were successfully reduced to obtain mono-domain Bi2 Te3 thin films without any domain boundaries using the 2°-miscut GaAs substrates, where a particular step-and-terrace structure on the vicinal surface macroscopically broke the intrinsic symmetry of GaAs, lowering the number of possible domains. Depending on the miscut directions, the in-plane orientations of the mono-domain Bi2 Te3 films were varied with respect to the GaAs substrate. A model was proposed to explain the effect of miscut substrate on the domain structure of Bi2 Te3 thin films. Low-temperature Hall measurements revealed that in the intrinsic regime (10 K) the electron concentration of the mono-domain Bi2 Te3 films (~2 × 10 18 cm −3 ) was significantly lower than that of the two-domain films (~10 19 cm −3 ). This was attributed to the donor-like effect of the 60° domain boundaries. These results provide an opportunity not only to integrate the single-crystalline, mono-domain, layered-chalcogenides on semiconductor single crystals, but also to manipulate their electronic transport properties by domain engineering. Graphical abstract: Image, graphical abstract