Theoretical Study of Anisotropic Carrier Mobility for Two-Dimensional Nb₂Se₉ Material

Finding new materials with satisfying all the desired criteria for nanodevices is an extremely difficult work. Here, we introduce a novel Nb₂Se₉ material as a promising candidate, capable of overcoming some physical limitations, such as a suitable band gap, high carrier mobility, and chemical stability. Unlike graphene, it has a noticeable band gap and no dangling bonds at surfaces that deteriorate transport properties, owing to its molecular chain structure. Using density functional theory (DFT) calculations with deformation potential (DP) theory, we find that the electron mobility of 2D Nb₂Se₉ across the axis direction reaches up to 2.56 × 10³ cm² V^-1 s^-1 and is approximately 2.5-6 times higher than the mobility of other 2D materials, such as MoS₂, black phosphorous, and InSe, at room temperature. Moreover, the mobility of 2D Nb₂Se₉ is highly anisotropic (μ _a /μ _c ≈ 6.5). We demonstrate the potential of 2D Nb₂Se₉ for applications in nanoscale electronic devices and, possibly, mid-infrared photodetectors.