Adsorption of Te clusters on tellurene and MoS_2 monolayers: structural, electronic, and optical properties

Adsorption of small Te clusters on tellurene and MoS_2 monolayers have been studied within density functional framework. With adsorption on 2D monolayers, Te clusters show distortion in cluster geometry along with local distortions in the monolayer. Adsorption energy is found to be higher in Te_n$tellurene as compared to Te_n$MoS_2 , suggesting that there exists a strong interaction between Te clusters and tellurene substrate. Adsorption of clusters on monolayers results in the modification of the effective band gap of these monolayers. Analysis of the charge density difference profile shows that a certain amount of charge is transferred from the clusters to the substrates. This results in the redistribution of the charge. Our optical calculations for the interband transitions show that Te cluster creates quantum states inside of monolayers, which leads to increasing optical absorption of the system. Additional low-intensity absorption peak, in addition to the main peak, has been noticed in cluster-adsorbed MoS_2 monolayer for E ∥ C. The real part of the dielectric function reveals the existence of plasmon frequencies. We conclude that the cluster adsorption on different monolayers alters the electronic and dielectric properties of monolayers.