Layer Dependence of Dielectric Response and Water-Enhanced Ambient Degradation of Highly Anisotropic Black As

Hwanhui Yun; Supriya Ghosh; Prafful Golani; Steven J Koester; K Andre Mkhoyan

doi:10.1021/acsnano.0c01506

Layer Dependence of Dielectric Response and Water-Enhanced Ambient Degradation of Highly Anisotropic Black As

ACS Nano. 2020 May 26;14(5):5988-5997. doi: 10.1021/acsnano.0c01506. Epub 2020 Apr 23.

Authors

Hwanhui Yun¹, Supriya Ghosh¹, Prafful Golani², Steven J Koester², K Andre Mkhoyan¹

Affiliations

¹ Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States.
² Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States.

PMID: 32310631
DOI: 10.1021/acsnano.0c01506

Abstract

Black arsenic (BAs) is a van der Waals layered material with a puckered honeycomb structure and has received increased interest due to its anisotropic properties and promising performance in devices. Here, crystalline structure, thickness-dependent dielectric responses, and ambient stability of BAs nanosheets are investigated using scanning transmission electron microscopy (STEM) imaging and spectroscopy. Atomic-resolution high-angle annular dark-field (HAADF)-STEM images directly visualize the three-dimensional structure and evaluate the degree of anisotropy. STEM-electron energy loss spectroscopy is used to measure the dielectric response of BAs as a function of the number of layers. Finally, BAs degradation under different ambient environments is studied, highlighting high sensitivity to moisture in the air.

Keywords: 2D materials; EELS; HAADF-STEM; black arsenic; degradation; surface plasmon; thickness-dependent EELS.