Enhancing the adsorption performance and sensing capability of Ti-doped MoSe_2 and MoS_2 monolayers by applying electric field

摘要

On the basis of recent findings reported, gas sensors constructed from MoS2 and MoSe2 monolayers have superior sensing performance compared to the gas sensors fabricated from graphene. In this work, we scrutinized the adsorption of NO, and CO gas molecules on the perfect and Ti-doped MoS2 and MoSe2 monolayers by means of the density functional theory method. The obtained results revealed that the Ti-doped MoS2 and MoSe2 monolayers have more sensitivity towards NO and CO detection than the pristine systems with substantial adsorption energies of gas molecules on these surfaces. The higher sensitivity and larger adsorption energy of Tidoped systems are responsible for the strong interaction between NO/CO molecules and MoS2/MoSe2 systems. There are considerable electronic density between the metal site of substrates and N/C atoms of NO/CO molecules, which can be attributed to the strong interaction between them. Moreover, the effect of external electric field on the adsorption process was evaluated, which indicates that the sensitivity of gas sensor can substantially be modulated via applying external electric field. This work aims at suggesting a promising material based on Ti-doped MoS2 and MoSe2 systems for sensing toxic NO and CO gases in the atmosphere.