In Situ Thermal Decomposition of Exfoliated Two-Dimensional Black Phosphorus

• Published in: The journal of physical chemistry letters Vol. 6; no. 5; pp. 773 - 778
• Main Authors: Liu, Xiaolong, Wood, Joshua D, Chen, Kan-Sheng, Cho, EunKyung, Hersam, Mark C
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 05.03.2015
• Subjects: Nanostructures - chemistry; Phosphorus - chemistry; Surface Properties; thermal; black phosphorus; TEM; STEM; phosphorene; sublimation
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.5b00043

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.