Co-Operative Influence of O2 and H2O in the Degradation of Layered Black Arsenic

Abstract

Layered black arsenic (b-As) has recently emerged as a new anisotropic two-dimensional (2D) semiconducting material with applications in electronic devices. Understanding factors affecting the ambient stability of this material remains crucial for its applications. Herein, we use first-principles density functional theory calculations to examine the stability of the (010) and (101) surfaces of b-As in the presence of O2 and H2O. We show that the (101) surface of b-As can easily oxidize in the presence of O2. In the presence of moisture contained in the air, the oxidized b-As surfaces favorably react with H2O molecules to volatilize As in the form of As(OH)3 and AsO(OH), which results in the degradation of the b-As surface, predominantly across the (101) surface. These predictions are in good agreement with experimental electron microscopy observations, thus demonstrating the co-operative reactivity of O2 and H2O in the degradation of layered b-As under ambient conditions.