Defect Generation and Surface Functionalization on Epitaxial Blue Phosphorene by C₆₀ Adsorption

We present molecular beam epitaxial growth of blue phosphorene (BlueP), a new allotrope of black phosphorene, on Au(111) and its surface functionalization with fullerene (C₆₀) molecules by low-temperature scanning tunneling microscopy and scanning tunneling spectroscopy (STS). In contrast to the well-ordered aggregation on conventional surfaces, C₆₀ molecules favor to adsorb at the domain boundaries of BlueP and create defects and a disordered phase nearby. STS reveals a shift of the conduction band minimum of BlueP and a remarkable broadening of the lowest unoccupied molecular orbital of C₆₀, indicating an interfacial charge transfer. In addition, codeposition of C₆₀ with phosphorous precursors on Au(111) followed by annealing generates a new reconstruction of BlueP comprising larger triangles and higher density of dislocation lines that are favorable for anchoring bulky C₆₀ balls.