Firstly, the band gap of phosphorene adsorbed with Fe is reduced to 0.22 eV with some defect states in the band gap .
It is verified that phosphorene is a layer-dependent 2D material; the structure and electronic and magnetic properties of transition-metal adatoms on bilayer and few layers phosphorene have not been involved.
Phosphorene, owing to its remarkable features, such as a large direct band gap of 1.5 eV, a high on/off ratio of over [10.sup.4], and a high carrier mobility of up to 10000 [cm.sup.2][s.sup.-1][v.sup.-1], has become a new important 2D material.
In addition to being one of the few of these materials to actually be created in the lab, phosphorene has drawn attention because black phosphorus has been known for decades to have a band gap, meaning that it requires some energy for an electron to jump from a bound state (the valence band) into a free state (the conduction band), where it can flow in an electrical current.
Estimations of the band gap for single-layer phosphorene range from 1.2 to 2 eV.
What has researchers particularly excited about phosphorene, besides its very large band gap, is that the band gap appears to be tunable; varying the number of layers in the sample changes the effective band gap.
Most are only a single-layer of atoms thick but where the ribbon is formed of more than one layer of phosphorene, we have found seamless steps between 1-2-3-4 layers where the ribbon splits.
While nanoribbons have been made from several materials such as graphene, the phosphorene nanoribbons produced here have a greater range of widths, heights, lengths and aspect ratios.
"We were trying to make sheets of phosphorene so were very surprised to discover we'd made ribbons.
Generally, the model contains one metal atom on 4 X 3 primitive cells of phosphorene; thus the atomic concentration of adsorbed metal is 2.08%.
Being distinct from graphene with a planar structure, phosphorene monolayer has a puckered structure with P atoms arranged in a honeycomb lattice as shown in Figures 1(a) and 1(b).
"Nothing really comes close to graphene" in a variety of properties, said MIT chemical engineer Michael Strano, emphasizing phosphorene
's inferior charge transport speeds.