Theoretical study of the structure and photoelectrical properties of tellurium (Te) doped graphene with the external electrical field

Abstract

The models and photoelectrical properties of Te doped graphenes with different contents (1Te-G, 2Te-G, 3Te-G and 4Te-G) were built and analyzed by using DFT method, and their properties were also discussed under the external electric field (−0.6 to 0.6 eV/Å). The phonon dispersion and formation energy of Te doped graphenes indicated that their structures were stable and it can be synthesized by conventional methods. Moreover, the band gaps of Te doped graphens were increased from 0.434 eV, 0.521 eV, 0.588 eV to 0.990 (the indirect one is 0.910) eV with the increase of Te atoms content in the graphene, and the effective masses of electrons and holes were increased with the increase in the concentration of Te atom in Te doped graphen. Taking 4Te-G as example, its band gap was increased from 0.245 to 1.152 eV in the range −0.6 to 0.6 eV/Å. The optical analysis date indicated that the peak (dielectric function, refractive index, reflectivity and loss function) curves of Te doped graphenes in low frequency region were gradually red-shifted with the increase of Te atoms content in the graphene, and there was no significant change in the high frequency region. Under the applied electric field, their corresponding peaks curve were not changed in the low frequency. But under the action of a positive electric field, these peak curves with increased intensity were blue-shifted regardless of the magnitude of the applied electric field intensity. However, the negative electric field has the opposite effect.