Density functional studies of small silicon clusters adsorbed on graphene

Abstract

The structural and electronic properties of small Si_n clusters (n = 1–6, 10) adsorbed on graphene are studied by use of density functional theory within periodic boundary conditions. Our results show that the structural properties of the deposited Si_n clusters and graphene are weakly affected by their interaction. The adsorption energy difference of different adsorption sites for the same size Si cluster on graphene is very small, indicating the Si_n-cluster–graphene system will be obtained easily. There is a little charge transfer from Si_n clusters to graphene when the cluster size is larger. The adsorption of Si_n clusters will be an effective method to open of an energy gap for graphene, which is useful for the applications of graphene to electrical and optical devices. Especially, the adsorption of Si_n cluster with large size (n ≥ 5) would have a band gap with a constant energy value.