In Situ Thermal Decomposition of Exfoliated Two-Dimensional Black Phosphorus.
With a semiconducting band gap and high charge carrier mobility, two-dimensional (2D) black phosphorus (BP)—often referred to as phosphorene—holds significant promise for next generation electronics and optoelectronics. However, as a 2D material, it possesses a higher surface area to volume ratio than bulk BP, suggesting that its chemical and thermal stability will be modified. Herein, an atomic-scale microscopic and spectroscopic study is performed to characterize the thermal degradation of mechanically exfoliated 2D BP. From in situ scanning/transmission electron microscopy, decomposition of 2D BP is observed to occur at ∼400 °C in vacuum, in contrast to the 550 °C bulk BP sublimation temperature. This decomposition initiates via eye-shaped cracks along the [001] direction and then continues until only a thin, amorphous red phosphorus like skeleton remains. In situ electron energy loss spectroscopy, energy-dispersive X-ray spectroscopy, and energy-loss near-edge structure changes provide quantitative insight into this chemical transformation process.
†Graduate Program in Applied Physics, Northwestern University, Evanston, Illinois 60208, United States.
Xiaolong
X
Liu
‡Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.
Joshua D
JD
Wood
‡Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.
Kan-Sheng
KS
Chen
‡Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.
EunKyung
E
Cho
†Graduate Program in Applied Physics, Northwestern University, Evanston, Illinois 60208, United States.|‡Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.|§Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.|∥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States.
Mark C
MC
Hersam
D049329:Nanostructures / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry*; D013499:Surface Properties
D010758:Phosphorus
STEM; TEM; black phosphorus; phosphorene; sublimation; thermal