Abstract
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 language | English (US) |
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Pages (from-to) | 12416-12423 |
Number of pages | 8 |
Journal | ACS nano |
Volume | 12 |
Issue number | 12 |
DOIs | |
State | Published - Dec 26 2018 |
Keywords
- 2D materials
- GeAs
- linear dichroism
- optical reversal
- polarization-sensitive
ASJC Scopus subject areas
- General Materials Science
- General Engineering
- General Physics and Astronomy