Highly stable two-dimensional gold selenide with large in-plane anisotropy and ultrahigh carrier mobility

摘要

The discovery of 2D anisotropic semiconductors with high carrier mobility is critical for highly efficient polarization-sensitive devices.Here,we explore the unique properties of an unexpected,yet highly-promising 2D chalcogenide,gold selenide(AuSe) with high stability,ultrahigh and anisotropic carrier mobilities.Linear(Au~(IV)) and square-planar(Au~(IV)) channels coexist in 2D AuSe,leading to the remarkable in-plane anisotropy.Electrons favour transport along the a direction with mobility up to 3.98 × 104 cm~2(V s)~(-1),whereas hole mobility along the b direction(over 8000 cm~2(V s)~(-1)) is almost 40 times larger than that along the a direction.The carrier mobility of 2D AuSe is much higher than most widely-studied 2D semiconductors,such as MoS2 and phosphorene.Moreover,2D AuSe shows almost full spectral solar absorption,relying on the proper bandgaps.The combination of the separation of ultrafast electron and hole transport channels(Au~(IV) and Au~(II)) and efficient solar absorption enables 2D AuSe great potentials in multifunctional optoelectronics.