Violet phosphorus surface chemical degradation in comparison to black phosphorus

Bulk growth methods have made it possible to synthesize several allotropes of phosphorus such as black, white, red, and violet phosphorus. However, unlike exfoliated black phosphorus (BP), which has been extensively studied, much of the optoelectronic properties and stability of the other allotropes have yet to be comprehensively investigated. Here, we study the chemical degradation of exfoliated violet phosphorus (VP) in comparison to BP under ambient conditions using nanoscale infrared spectroscopy and imaging. We identify oxidized phosphorus species that result from chemical reaction processes on the surfaces of these phosphorus allotropes. We have found that VP exhibits a noticeably different and slower degradation process when compared to BP, establishing it as the more stable of the two allotropes. A better understanding of the stability of VP could lead to the further fundamental study of its monolayer form for potential future applications.