Highly In‐Plane Anisotropic 2D GeAs₂ for Polarization‐Sensitive Photodetection

Abstract

Due to the intriguing anisotropic optical and electrical properties, low‐symmetry 2D materials are attracting a lot of interest both for fundamental studies and fabricating novel electronic and optoelectronic devices. Identifying new promising low‐symmetry 2D materials will be rewarding toward the evolution of nanoelectronics and nano‐optoelectronics. In this work, germanium diarsenide (GeAs2), a group IV–V semiconductor with novel low‐symmetry puckered structure, is introduced as a favorable highly anisotropic 2D material into the rapidly growing 2D family. The structural, vibrational, electrical, and optical in‐plane anisotropy of GeAs2 is systematically investigated both theoretically and experimentally, combined with thickness‐dependent studies. Polarization‐sensitive photodetectors based on few‐layer GeAs2 exhibit highly anisotropic photodetection behavior with lineally dichroic ratio up to ≈2. This work on GeAs2 will excite interests in the less exploited regime of group IV–V compounds.

Emerging in‐plane anisotropic two‐dimensional materials

“…Moreover, Guo et al reported a polarization‐sensitive medium wavelength infrared BP phototransistor, which can operate at wavelength of 3.39 μm and at low power in picowatts range . Figure F shows the typical schematic of the polarization‐sensitive photodetector of GeAs 2 , similar polarization‐sensitive photodetectors have also been fabricated on ReS 2 GeSe, ReSe 2 and ReS 2 Se 2(1‐ x ) . Recently, our group reported the polarization‐sensitive photodetector based on highly anisotropic 2D GeAs 2 with a dichroic ratio up to 2, and we found that polarization‐dependent photocurrent stem from GeAs 2 itself, since both the polarization‐dependent photoreponse and reflectance contrast display similar polarization‐dependent behavior .…”

“…Reproduced with permission from ref. Copyright 2018, Wiley‐VCH. G, Anisotropic photocurrent response of TaIrTe 4 .…”

“…Figure F shows the typical schematic of the polarization‐sensitive photodetector of GeAs 2 , similar polarization‐sensitive photodetectors have also been fabricated on ReS 2 GeSe, ReSe 2 and ReS 2 Se 2(1‐ x ) . Recently, our group reported the polarization‐sensitive photodetector based on highly anisotropic 2D GeAs 2 with a dichroic ratio up to 2, and we found that polarization‐dependent photocurrent stem from GeAs 2 itself, since both the polarization‐dependent photoreponse and reflectance contrast display similar polarization‐dependent behavior . Xu and coworkers demonstrated that the photocurrent of these Re‐based dichalcogenides photodetectors show maximum values when the incident light is polarized along the b axis, and minimum values when the incident light is polarized perpendicular to b axis .…”

Chemical and Electrochemical Lithiation of van der Waals Tetrel‐Arsenides

“…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 …”

Low‐Energy GeP Monolayers with Natural Type‐II Homojunctions for SunLight‐Driven Water Splitting

“…Binary alloys of group IV–V elements (AB, A═Si, Ge and B═P, As) adopting layered structures provide us another family of 2D materials. Based on the well‐known top‐to‐down synthesizing strategy, few‐layered group IV–V compounds have been experimentally realized . These 2D group IV–V compounds have attracted much scientific interests due to their highly anisotropic properties benefit from their low‐symmetry structures.…”