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

Abstract

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.

Interfacial Effects on the Growth of Atomically Thin Film: Group VA Elements on Au(111)

“…Increasing the coverage to 0.8 ML, BlueP on Au(111) still preserves its honeycomb structure, while several holes are filled with P atoms (circles in Figure a,b). The dark‐colored lines in Figure a are domain boundaries between unidirectionally aligned BlueP islands, including dislocation lines, defective chains, and big holes . In the case of Sb, high coverage generates a new phase along with the disappearance of dispersed bright dots, as shown in Figure c.…”

Recent progress in epitaxial growth of two‐dimensional phosphorus

“…Stable in‐situ substitutional doping during the synthesis of 2D phosphorus (e.g., nitrogen doping of BlueP 79 ) represents a promising approach to extend their application in multifunctional devices, but is rarely investigated. It is also important to explore other nondestructive doping strategies, for example, combining with other organic 89,90 and inorganic quantum materials 91,92 to construct 2D phosphorus‐based heterojunctions.…”

Phosphorene–Fullerene Nanostructures: A First-Principles Study

“…Compared to our results, periodic vdW-KBM calculations and molecular dynamics simulations have reported non-covalent Phos−C60 complexes with Eads values of 0.7 and −1.0 eV, respectively 19,23 ; then, our results agree with previous reports. Additionally, UV-VIS-NIR absorbance, temperature scanning tunneling microscopy, and scanning tunneling spectroscopy measurements indicate that C60 molecules physically adsorb on phosphorene, where desorption occurs with annealing 400 K [20][21] . As can be seen, Eads=0.9 eV for Phos−C60 complexes agrees with the experimental favorable non-covalent adsorption of fullerenes on phosphorene-based materials.…”

“…Mechanochemical reactions in a high energy mechanical milling process have been used as a strategy to form phosphorus-carbon (P−C) bonds between phosphorene and carbon materials, including C60, graphite, and graphite oxide 16 ; in this way, the content of the P−C bond in the phosphorene-C60 hybrids is only 0.8%, denoting C60 is not preferably bonded to phosphorene via covalent interactions until breaking the sp 2 C=C/C−C bonds to form defects 16 . In addition, low-temperature scanning tunneling microscopy, X-ray, ultraviolet photoelectron, and scanning tunneling spectroscopy measurements also show that C60 molecules are mainly physisorbed at room temperature on the honeycomb lattice of blue and black phosphorene synthesized by epitaxial growth, where an interfacial charge transfer is evidenced upon interaction with C60 [21][22] .…”