Defect Characterization and Engineering in Black Phosphorus

A tunable band gap and high carrier mobility make black phosphorus (BP) attractive for device applications. To effectively engineer micron scale BP devices, it is essential to understand defects down to the atomic level. The most prominent defects on the surface of BP exhibit a large electronic signature in scanning tunneling microscopy (STM) images. We previously found that the predominant defects in BP are vacancies and are the source of p-doping in the material. These studies demonstrate the need for vacancy formation control during synthesis. Here, we will describe STM experiments of BP that further characterize the defects and explore defect control and creation through ultra high vacuum annealing.