Perpendicular Optical Reversal of the Linear Dichroism and Polarized Photodetection in 2D GeAs

Ziqi Zhou, Mingsheng Long, Longfei Pan, Xiaoting Wang, Mianzeng Zhong, Mark Blei, Jianlu Wang, Jingzhi Fang, Sefaattin Tongay, Weida Hu, Jingbo Li, Zhongming Wei

Research output: Contribution to journalArticlepeer-review

117 Scopus citations


The ability to detect linearly polarized light is central to practical applications in polarized optical and optoelectronic fields and has been successfully demonstrated with polarized photodetection of in-plane anisotropic two-dimensional (2D) materials. Here, we report the anisotropic optical characterization of a group IV-V compound-2D germanium arsenic (GeAs) with anisotropic monoclinic structures. High-quality 2D GeAs crystals show the representative angle-resolved Raman property. The in-plane anisotropic optical nature of the GeAs crystal is further investigated by polarization-resolved absorption spectra (400-2000 nm) and polarization-sensitive photodetectors. From the visible to the near-infrared range, 2D GeAs nanoflakes demonstrate the distinct perpendicular optical reversal with a 75-80° angle on both the linear dichroism and polarization-sensitive photodetection. Obvious anisotropic features and the high dichroic ratio of I pmax /I pmin ∼ 1.49 at 520 nm and I pmax /I pmin ∼ 4.4 at 830 nm are achieved by the polarization-sensitive photodetection. The polarization-dependent photocurrent mapping implied that the polarized photocurrent mainly occurred at the Schottky photodiodes between electrode/GeAs interface. These experimental results are consistent with the theoretical calculation of band structure and band realignment. Besides the excellent polarization-sensitive photoresponse properties, GeAs-based photodetectors also exhibit rapid on/off response. These results demonstrate that the 2D GeAs crystals have promising potential for polarization optical applications.

Original languageEnglish (US)
Pages (from-to)12416-12423
Number of pages8
JournalACS nano
Issue number12
StatePublished - Dec 26 2018


  • 2D materials
  • GeAs
  • linear dichroism
  • optical reversal
  • polarization-sensitive

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)


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