Dipole Orientation Shift of Ga<sub>2</sub>Se<sub>2</sub> by Quantum Confinement.

Xiao, Ke; Yan, Tengfei; Cui, Xiaodong · ACS Nano · 2020

basic_science · Level V

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Abstract

In the family of III-VI monochalcogenides M<sub>2</sub>X<sub>2</sub> (M = gallium, indium; X = sulfur, selenide, <i>etc.</i>), the interlayer interaction and the electronic band edges share the contribution of the same chalcogenide atomic orbits. This makes quantum confinement and interlayer interaction play a subtle role in two-dimensional (2D) monochalcogenides crystals. In this report, we study the direction-resolved photoluminescence of 2D Ga<sub>2</sub>Se<sub>2</sub> at various thicknesses. We observe that the in-plane dipole radiation survives, but out-of-plane dipole radiation fades at 2D limits.