First-principles study of O-functionalized two-dimensional AsP monolayers: electronic structure, mechanical, piezoelectric, and optical properties

Abstract

Using density functional theory, we investigated the geometrical properties, electronic structures, carrier mobilities, piezoelectric coefficients, and optical absorption behaviors of three O-functionalized β-phase AsP structures (b-AsPO-FO, b-AsPO-As-SO and b-AsPO-P-SO). It is shown that three O-functionalized monolayers are all indirect semiconductors with bandgaps of 0.21, 0.67, and 0.80 eV, respectively. Our calculations demonstrated that the pristine AsP monolayer and these O-functionalized AsP monolayers have strongly anisotropic carrier mobilities, allowing their potential applications for in-plane anisotropic electronic device. The bandgaps of three functionalized nanomaterials exhibit non-monotonic variations under the biaxial strains changing from −0.10 to +0.10, all experiencing metal-indirect bandgap-direct bandgap transition. The calculated in-plane Young’s modulus results suggest that they are fairly flexible to allow the application of large elastic strains on the chemically functionalized AsP monolayers. Furthermore, the b-AsPO-FO monolayer exhibits excellent anisotropic light-harvesting behavior (absorption peak: 2.36 and 2.76 eV along x and 2.37 eV along y direction) in visible light region. The b-AsPO-As-SO and b-AsPO-P-SO monolayers have strong absorption peak at 2.60 eV and 2.87 eV, respectively. The tunable electronic structures, anisotropic carrier mobility, and excellent optical absorption properties may facilitate practical applications of O-functionalized b-AsP monolayers in nanoelectronics and photovoltaics.