Anisotropic optical and electronic properties of two-dimensional layered germanium sulfide
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- 作者：Dezhi Tan ; Hong En Lim ; Feijiu Wang ; Nur Baizura Mohamed ; Shinichiro Mouri…
- 关键词：germanium sulfide ; anisotropic optical property ; 2D layered materials ; photoluminescence ; polarized optical spectroscopy
- 刊名：Nano Research
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：10
- 期：2
- 页码：546-555
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Nanotechnology; Materials Science, general; Atomic/Molecular Structure and Spectra; Condensed Matter Physics; Biotechnology; Biomedicine, general;
- 出版者：Tsinghua University Press
- ISSN：1998-0000
- 卷排序：10
文摘
Two-dimensional (2D) layered materials, transition-metal dichalcogenides, and black phosphorus have attracted considerable interest from the viewpoints of fundamental physics and device applications. The establishment of new functionalities in anisotropic layered 2D materials is a challenging but rewarding frontier, owing to the remarkable optical properties of these materials and their prospects for new devices. Herein, we report the anisotropic and thickness-dependent optical properties of a 2D layered monochalcogenide of germanium sulfide (GeS). Three Raman-scattering peaks corresponding to the B3g, Ag1, and Ag2 modes with a strong polarization dependence are demonstrated in the GeS flakes, which validates polarized Raman spectroscopy as an effective method for identifying the crystal orientation of anisotropic layered GeS. Photoluminescence (PL) is observed with a peak at ~1.66 eV that originates from the direct optical transition in GeS at room temperature. The polarization-dependent characteristics of the PL, which are revealed for the first time, along with the demonstration of anisotropic absorption, indicate an obvious anisotropic optical transition near the band edge of GeS, which is supported by density functional theory calculations. The significantly thickness-dependent PL is observed and discussed. This anisotropic layered GeS presents opportunities for the discovery of new physical phenomena and will find applications that exploit its anisotropic properties, such as polarization-sensitive photodetectors.