In-plane optical and electrical anisotropy in low-symmetry layered GeS microribbons

Zhangfu Chen, Woohyun Hwang, Minhyun Cho, Anh Tuan Hoang, Minju Kim, Dongwoo Kim, Dong Ha Kim, Young Duck Kim, Hyun Jae Kim, Jong Hyun Ahn, Aloysius Soon, Heon Jin Choi

Research output: Contribution to journalArticlepeer-review

Abstract

Layered group-IV monochalcogenides, including GeS, GeSe, SnS, and SnSe, garner attention because of their anisotropic structures and properties. Here, we report on the growth of GeS microribbons via chemical vapor transport (CVT), which affords each of them with a low-symmetry orthorhombic structure and anisotropic optical and electronic properties. The single-crystalline nature of the GeS microribbon, which has a typical thickness of ~30 nm, is confirmed. Polarized Raman spectra reveal angle-dependent intensities that are attributed to the anisotropic layered structure of GeS microribbons. The photoluminescence (PL) spectra reveal a peak at ~1.66 eV. The angle-dependent PL and anisotropic absorption spectroscopy results provide evidence for a distinct anisotropic optical transition near the energy band edges; this phenomenon is also predicted by our density functional theory (DFT)-based calculations. Strong in-plane direct-current transport anisotropy is observed under dark and white illumination by using back-gate cross-shaped field effect transistors (CSFETs) fabricated with the GeS microribbon; significant gate-tunable conductivity is also confirmed. The strong anisotropy is further confirmed by the DFT-calculated effective mass ratio. Our findings not only support the application of GeS microribbons in anisotropic photoelectronic transistors but also provide more possibilities for other functional device applications.

Original languageEnglish
Article number41
JournalNPG Asia Materials
Volume14
Issue number1
DOIs
Publication statusPublished - 2022 Dec

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation (NRF) of Korea funded by the Ministry of Science and ICT under the Creative Materials Discovery Program (2018M3D1A1058536). Computational resources were provided by the Korean Institute of Science and Technology Information (KISTI) supercomputing center through the strategic support program for supercomputing application research (KSC-2019-CRE-0174).

Funding Information:
This work was supported by the National Research Foundation (NRF) of Korea funded by the Ministry of Science and ICT under the Creative Materials Discovery Program (2018M3D1A1058536). Computational resources were provided by the Korean Institute of Science and Technology Information (KISTI) supercomputing center through the strategic support program for supercomputing application research (KSC-2019-CRE-0174).

Publisher Copyright:
© 2022, The Author(s).

All Science Journal Classification (ASJC) codes

  • Modelling and Simulation
  • Materials Science(all)
  • Condensed Matter Physics

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