Perpendicular Optical Reversal of the Linear Dichroism and Polarized Photodetection in 2D GeAs
Author(s): Zhou, ZQ (Zhou, Ziqi); Long, MS (Long, Mingsheng); Pan, LF (Pan, Longfei); Wang, XT (Wang, Xiaoting); Zhong, MZ (Zhong, Mianzeng); Blei, M (Blei, Mark); Wang, JL (Wang, Jianlu); Fang, JZ (Fang, Jingzhi); Tongay, S (Tongay, Sefaattin); Hu, WD (Hu, Weida); Li, JB (Li, Jingbo); Wei, ZM (Wei, Zhongming)
Source: ACS NANO Volume: 12 Issue: 12 Pages: 12416-12423 DOI: 10.1021/acsnano.8b06629 Published: DEC 2018
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 aniso-tropic 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 photo-detectors. From the visible to the near-infrared range, 2D GeAs nanoflakes demonstrate the distinct perpendicular optical reversal with a 75-80 degrees angle on both the linear dichroism and polarization-sensitive photodetection. Obvious anisotropic features and the high dichroic ratio of I-pmax /I-pmin similar to 1.49 at 520 nm and I-pmax/I-pmin similar to 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.
全文链接:https://pubs.acs.org/doi/abs/10.1021%2Facsnano.8b06629