Layer-Dependent Electronic Structure of Atomically Resolved Two-Dimensional Gallium Selenide Telluride

Journal Article · Tue Feb 12 00:00:00 EST 2019 · Nano Letters

DOI:https://doi.org/10.1021/acs.nanolett.8b04802· OSTI ID:1542380

Azizi, Amin  ^[1]; Antonius, Gabriel ^[2]; Regan, Emma ^[3]; Eskandari, Rahmatollah ^[4]; Kahn, Salman ^[5]; Wang, Feng ^[6]; Louie, Steven G.  ^[5]; Zettl, Alex ^[6]

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1. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Univ. of California, Berkeley, CA (United States). Kavli Energy NanoScience Inst.
2. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Univ. du Québec à Trois-Rivières, Trois-Rivières, QC (Canada)
3. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Univ. of California, Berkeley, CA (United States). Graduate Group in Applied Science and Technology
4. Univ. of California, Berkeley, CA (United States). Dept. of Physics
5. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
6. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Univ. of California, Berkeley, CA (United States). Kavli Energy NanoScience Inst.; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division

Alloying two-dimensional (2D) semiconductors provides a powerful method to tune their physical properties, especially those relevant to optoelectronic applications. However, as the crystal structure becomes more complex, it becomes increasingly difficult to accurately correlate response characteristics to detailed atomic structure. We investigate, via annular dark-field scanning transmission electron microscopy, electron energy loss spectroscopy, and second harmonic generation, the layered III-VI alloy GaSe_0.5Te_0.5 as a function of layer number. The local atomic structure and stacking sequence for different layers is explicitly determined. We complement the measurements with first-principles calculations of the total energy and electronic band structure of GaSe_0.5Te_0.5 for different crystal structures and layer number. The electronic band gap as well as the π and π + σ plasmons are found to be sensitive to layer number.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1542380
• Journal Information: Nano Letters, Vol. 19, Issue 3; ISSN 1530-6984
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
2D semiconductor alloys
GaSe0.5Te0.5
electronic structure
atomic structure
stacking order