Ultra-strong anisotropic photo-responsivity of bilayer tellurene: a quantum transport and time-domain first principle study

Abstract

Abstract Unlike traditional two-dimensional layered materials, tellurium (Te) shows its one-dimensional van der Waals structure and triggers intensive researches. Through a density functional theory coupled with the nonequilibrium Green’s function calculation, we found that bilayer tellurene has a broad photoelectric response over the range from the visible to the near-infrared region. Besides, bilayer tellurene photodetector presents an ultra-strong anisotropic photo-responsivity and an ultra-high extinction ratio (~2812 at the photon energy of 3.4 eV) because of its non-layer/chain structure, which is superior to the antimonene (~145) and phosphorene/blue phosphorene bilayers (~240). Time-domain first principle study further reveals that the ultra-strong anisotropy comes from the transition of Te 5p bonding orbitals along or perpendicular to the chain directions. With these excellent optoelectronic merits, bilayer tellurene may become a promising candidate for next-generation photoelectronic devices.