Hydrocarbon contamination and deposition in a scanning transmission electron microscope (STEM) is generally considered a detriment. Techniques such as plasma cleaning and thermal annealing are designed specifically to reduce or prevent hydrocarbon contamination. While contamination is clearly a detriment to the vast majority of microscopy studies, here we seek to address how such contamination may be useful, as it relates to nanometer-scale in situ material manipulation. There have been exciting recent developments in atomic scale material control in the STEM where single Si atoms have been controllably moved through a graphene lattice via e-beam manipulation.1-3 This is exciting for several reasons, 1) the STEM has the capability of focusing the probe onto single atoms in graphene so that addressing individual atoms is possible, 2) individual atomic species may be determined via image intensity or single atom spectroscopy, and 3) structures fabricated can be directly imaged during fabrication. Given this progress toward atomic manipulation in graphene, it is worth exploring additional material control mechanisms with this material system. Given, also, that mechanisms for material manipulation in STEM are limited mostly to e-beam exposure, we approach this topic from the perspective of exploration: if some process is observed (i.e. hydrocarbon deposition), can we control when it occurs, can we precisely control the process (i.e. deposit a single layer of graphene), can we use this phenomenon in a larger process chain? Answering such questions will establish reliable capabilities which will expand the toolbox of material control techniques available in STEM. Here we will highlight several interesting examples where we make use of the ubiquitously observed hydrocarbon deposition in STEM to controllably pattern structures, heal holes, remove dopant atoms from the graphene lattice, and move nanoparticles. Exploring such capabilities is necessary in the pursuit of developing general atomic scale material control in a STEM.
1. S. Toma, K. Demie, L. Yung-Chang, M. R. Quentin, C. M. Jannik, S. Kazu and K. Jani, 2D Materials 4 (4), 042004 (2017).
2. O. Dyck, S. Kim, S. V. Kalinin and S. Jesse, Applied Physics Letters 111 (11), 113104 (2017).
3. O. Dyck, S. Kim, E. Jimenez-Izal, A. N. Alexandrova, S. V. Kalinin and S. Jesse, ArXiv e-prints,