Dresden 2020 – scientific programme
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DS: Fachverband Dünne Schichten
DS 35: 2D Materials and their Heterostructures II (joint session DS/HL/O)
DS 35.5: Talk
Thursday, March 19, 2020, 10:30–10:45, CHE 89
First-principles study of hydrogenation on bilayer GaN — •Anh Khoa Augustin Lu1, Tetsuya Morishita1,2, Tomoe Yayama3, and Takeshi Nakanishi1,2 — 1MathAM-OIL, AIST, Sendai, Japan — 2CD-FMat, AIST, Tsukuba, Japan — 3Department of Applied Physics, Kogakuin University, Tokyo, Japan
In the last decade, a large number of two-dimensional materials has been discovered. In recent years, two-dimensional III-V materials have arisen with the experimental demonstration of two-dimensional GaN. Here, we focus on the case of bilayer GaN. While the atomic structure of pristine bilayer GaN is relatively well understood, the impact that hydrogenation remains unclear since unlike transition metal dichalcogenides, pristine GaN has dangling bonds. In that respect, the present work focuses on the atomic structure, stability and electronic properties of bilayer GaN passivated by hydrogen atoms, with a large range of hydrogen coverage. First-principles calculations based on the density functional theory were performed to identify the structures with the lowest energy. While previous studies have focused on structures oriented along the c-plane, our results reveal that depending on the hydrogen concentration, the plane orientation of the most stable structure (c-, m-, or a-plane) is different. In particular, at high hydrogen concentration, structures oriented along the m- and a-planes have the lowest energy. Their stability is confirmed by first-principles molecular dynamics simulations performed at finite (room) temperature. By modulating the hydrogen concentration, one can therefore tailor the atomic structure and properties of bilayer GaN.