As₂O₃ as an inorganic molecular crystal: a DFT study for nanoelectronics

This study explores the structural, electronic and transport properties of arsenic oxide (As₂O₃) in its bulk form and two-dimensional surfaces, where the surfaces were cut at specific lattice planes, i.e. (001), (110) and (111), and represented as slab-(001), slab-(110) and slab-(111), respectively. The structural properties reveal that As₂O₃ shows potential as an inorganic molecular crystal (IMC) because of its three-dimensional anisotropy. Formation energy computations confirm the structural stability of As₂O₃ in its bulk and respective surface counterparts, and the mechanical stability of the materials is determined by calculating the elastic tensors and subsequent elastic constants. Electronic structure computations indicate that As₂O₃ is a wide-band-gap material in its bulk and surfaces along the (001) and (110) crystal planes, whereas the (111) surface indicates narrow-band-gap behavior. This wide band gap of the material can be attributed to the specific crystal structure of the IMC. Investigations on the bulk modulus, Young's modulus, shear modulus and Poisson's ratio reveal that the material exhibits favorable mechanical properties. Furthermore, the Poisson's ratio and B/G ratio show the brittle nature of the material. Besides these, using the non-equilibrium Green's function (NEGF) formalism, the transport properties of the narrow-band-gap slab-(111) and slab-(001) were investigated to determine their potential for application in nano-devices, and the current-voltage (I-V) profile revealed that slab-(111) has potential to be used as a Schottky device, whereas slab-(001) exhibited an ohmic nature.