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

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.

Chemical and Electrochemical Lithiation of van der Waals Tetrel‐Arsenides

“…Binary GeAs and SiAs compounds, which have been known for decades, have mostly been overlooked in terms of properties until recently . These isostructural compounds are built of covalently bonded Si‐As or Ge‐As layers held together by weak van der Waals interactions.…”

“…Layered tin phosphide, Sn 4 P 3 , has been studied for lithium‐ion and sodium‐ion battery applications and has been proven to be a promising material . Pnictides of lighter tetrels such as GeAs, SiAs, GeP, SiP, GeAs 2 , and SiAs 2 have been gaining interest in the field of thermoelectrics, photovoltaics, water splitting, and optics owing to their anisotropic nature, weak interlayer interactions, relatively small band gaps (<2 eV), and potential for tuning of properties through doping and strain …”

“…[12][13][14][15][16] Pnictides of lighter tetrels such as GeAs, SiAs, GeP,S iP,G eAs 2 , and SiAs 2 have been gaining interesti nt he field of thermoelectrics, photovoltaics, water splitting,a nd optics owing to their anisotropic nature, weak interlayer interactions, relatively small band gaps (< 2eV), and potentialf or tuning of properties through doping and strain. [4][5][6][7][8][9][17][18][19][20][21][22][23] Numerous layered ATt 3 Pn 3 (A = Na-Rb;T t= Si or Ge;P n= P or As) ternary phases have been reported in the literature; however,n one have included lithium as the alkali metalt ot he best of our knowledge. [24,25] For the larger sodium cation, a NaGe 6 As 6 structure was reported , which retains the layered structure and bondingi nb inary GeAs, but accommodates the Na atom through shifting of the layers.…”

Symmetry‐Reduction Enhanced Polarization‐Sensitive Photodetection in Core–Shell SbI3/Sb2O3 van der Waals Heterostructure

“…Since the discovery of graphene, the increasingly 2D materials have great application prospects in nanoelectronics and nanooptoelectronics due to the unique crystal structure and physical properties. Currently, anisotropic physical properties of 2D materials, such as black phosphorus (BP) and GeAs, have attracted intensive attention in polarization‐sensitive photodetection field, and the devices exhibited desirable performance. Among these 2D materials, BP as an example possessed high anisotropic and considerable photoelectronic properties .…”

Tunable Electronic Properties and Potential Applications of 2D GeP/Graphene van der Waals Heterostructure

“…Recent experimental demonstrations have shown the achievement of few‐layered GeAs field effect transistors (FET) with p‐type behaviors at room temperature and an impressive hole carrier mobility of approaching 100 cm 2 V −1 s −1 17. The 2D IV‐V semiconductors exhibit highly anisotropic optical and electronic properties due to their unique atomic strucutre 15–20. The strong in‐plane anisotropy can give rise to novel properties and offer new opportunities to effectively tune the optical and electrical transport properties, facilitating the practical applications of the 2D IV‐V semiconductors 3,16,21…”